Category: ICSE Solutions

Frank ICSE Solutions for Class 9 Physics – Sound: Production and Propagation of Sound

PAGE NO: 278
Solution 1:
Yes, Sound is form of energy.

Solution 2:
Sound is produced by the vibrating objects.

Solution 3:
No, sound cannot travel through vacuum.

Solution 4:
Yes, sound can propagate through solids and liquids.

Solution 5:
No, sound cannot be produced in vacuum. It needs a material medium.

Solution 6:
Speed of sound depends on the density, pressure, temperature, humidity and Wind.

Solution 7:
330m/s is the value of speed in air at N.T.P

Solution 8:
In water, speed of sound is 4.5 times more than that in air. And, in iron, the speed of sound is 15 times as fast in air.

Solution 9:
The speed of sound is more in the humid air as compared to dry air. Because, the air moisture decreases the density of air and speed of sound is inversely proportional to density of air. So, sound travels faster in humid air.

Solution 10:
Speed of sound does not depend on the amplitude and wavelength.

Solution 11:
The sound produced by the moving wheels of the train travels faster on the iron track than in the air. So, firstly sound produced because of railway track is heard and then heard in the air.

Solution 12:
The waves in the air causes sound . Through waves , energy get transferred from one place to another and hence the sound.

Solution 13:
The ratio of speed of light to the speed of sound is 9.1 x 10⁵.

Solution 14:
Speed of sound in air is independent of variation of pressure.

Solution 15:
The speed of sound in air increases with increase in temperature because with increase in temperature, the density of air gases decreases and speed of air is inversely proportional to density of air.

Solution 16:
The diver will hear the sound first because the sound travels faster in water than in air.

Solution 17:
The simple experiment that a person can do to calculate the speed of sound in air is that a person stands at a known distance (d meter) from the cliff and fires a pistol and simultaneously start the stop watch. He stops the stop-watch as soon as he hears a echo. The distance travelled by the sound during the time (t) seconds is 2d.
So, speed of sound = distance travelled / time taken = 2d/t

Solution 18:

• Moisture in Air: The speed of sound increase with increase in humidity because the moisture in air decrease the density of air and speed of air is inversely proportional to density of air. Hence , the sound travels faster in moist air.
• Pressure in air: Speed of sound is independent of the air pressure.
• The speed of sound increases with the increase in temperature of the gas.

Solution 19:
The distance of flash from the observer = speed in air x time taken for the first sound to reach 330 x 6 = 1980m

Solution 20:
Distance between boys = speed of sound x time taken to reach sound = 330 x 2.5 = 825m

PhysicsChemistryBiologyMaths

Frank ICSE Solutions for Class 9 Biology – Respiratory System

PAGE NO:176

Solution 1:
Respiration: It is a process of release of energy from food substances such as glucose and fats under the control of enzymes, to carry out life processes, by the living organisms.
Respiration is essential for life as energy produced during this process is utilized by the organisms to carry out various biological activities.

Solution 2:
Structure of nasal chamber:
The nasal chamber is divided into left and right chambers by nasal septum. Each chamber is divided into three regions –

1. Vestibule: It is the anterior most part of nasal chambers bearing hairs which filters the dust particles.
2. Respiratory region: It is rich in mucous glands and marked by nasal turbinates which traps the dust and humidify the air.
3. Olfactory chamber: It is lined by olfactory epithelium which sense the smell.

Solution 3:
Turbinates: The respiratory region of nasal chamber is marked by three nasal turbinates.These are Ethmoturbinate, nasoturbinate and maxilloturbinates.
Function of turbinates: It increases the surface area, so that dust particles can be removed and air become humidified.

Solution 4:
Adam’s apple : It is a prominent elevation formed by the laminae of thyroid cartilage. It is more pronounced in male than female.

Solution 5:

Solution 6:
The function of lecithin film in the lungs is to decrease the surface tension and keeps the alveoli open.

Solution 7:

Solution 8:
Breathing: It is the physical process of taking in oxygen and giving out carbon dioxide.
The function of diaphragm: It helps in breathing by contracting and relaxing thereby increase and decrease the volume of thoracic cavity. During inspiration diaphragm flattens while during expiration it becomes dome – shaped

Solution 9:

1. Cough Reflex: It is a type of reflex whose stimulus is any foreign particle which results from deep inspiration followed by strong expiration that forcefully expel the air through the mouth.
2.  Sneeze Reflex: It is a type of reflex whose stimulus is in the nasal passage which causes spasmodic contraction of expiratory muscles that forecefully expel the air through the nasal passage.
3.  Eupnea: Eupnea is a normal breathing.
4.  Dyspnea: A condition in which breathing is painful.
5. Apnea: A condition in which no breathing takes place.

Solution 10:
Internal respiration: It is the transport of oxygen in the blood from the lungs to the cells and the transport of carbon dioxide from the tissue cells into the blood and to the lungs.

Solution 11:
Respiratory quotient (RQ): It is the ratio of CO2 output to O2 uptake. It is denoted by R.
R = Rate of CO2 output / Rate of O2 uptake
RQ for carbohydrate = 1.00
RQ for fat = 0.70
RQ for protein = 0.85

Solution 12:
(i) Vestibule
(ii) Larynx
(iii) Alveoli
(iv) Lecithin
(v) Hyperpnea
(vi) Dyspnea
(vii) Apnea
(viii) Hypopnea
(ix) Thoracic cavity

Solution 13:
(i) Pleura
(ii) Eupnea
(iii) 500 cc
(iv) 0.70
(v) 38 ATP

Solution 14:

1.  Larynx = To produce voice
2. Alveoli = To increase the surface area for exchange of gases.
3. Conchae = It is also called turbinate and its function is to increase the surface area so that the dust particles can be removed and air become humidified.
4. Epiglottis = It closes the glottis during swallowing of food.
5. Lecithin covering = It lowers the surface tension and keeps the alveoli open.
6. Cartilaginous rings = It prevents the collapsing of trachea.

Solution 15:

1.  Alveoli – Gaseous exchange
2. Larynx – Sound production
3. Thoracic cage – Breathing

PAGE NO:177

Solution 16:

Solution 17:
(i)(b) Pleural membrane
(ii)(b) Alveoli
(iii)(d) All the above
(iv)(d) shows no change
(v)(d) 3000 – 4500 ml
(vi)(d) 158 and 116 mm Hg

BiologyChemistryPhysicsMaths

Frank ICSE Solutions for Class 9 Biology – Structure and Function of Skin

PAGE NO:169

Solution 1:
(a) Stratum corneum, transitional region, stratum germinativum
(b) Stratum germinativum
(c) Stratum corneum
(d) Dermis
(e) Sweat gland / sudoriferous gland
(f) Milk glands/ mammary glands
(g) Wax gland
(h) Epidermis
(i) Melanin

Solution 2:
(a) soles
(b) epidermis and dermis
(c) stratum corneum
(d) keratin
(e) mesoderm
(f) loose connective tissue
(g) sweat gland

Solution 3:
(a) True
(b) True
(c) True
(d) True
(e) False
(f) False

Solution 4:
(i) (a) stratum Malpighi
(ii) (d) palm
(iii) (b) stratum corneum
(iv) (b) dermis
(v) (b) dermis
(vi) (a) sweat gland
(vii) (c) constrict and the sweat glands are inactive

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Frank ICSE Solutions for Class 9 Biology – The Skeletal System

PAGE NO:162

Solution 1:
Bones of skull, vertebral column, sternum and ribs.

Solution 2:
Longest bone – Femur
Smallest bone – Stapes of middle ear.

Solution 3:
There are seven cervical vertebrae. First vertebra is called atlas, second is axis while the rest are called typical cervical vertebrae.

Solution 4:
The skeletal system performs the following functions in an animal:

1.  It provides a framework to support the body and gives a definite shape and form to the body.
2.  It helps to protect some of the vital organs like heart, lungs, brain and spinal cord.
3. It provides the base for attachment of muscles and several bones so as to make body movements possible.
4. Bones act as storehouse of some minerals like calcium and phosphorus.
5. Red bone marrow of long bones of limbs produces red blood cells and granulated white blood cells in their hollow cavities.

Solution 5:

1. Axial skeleton
2.  Appendicular skeleton

Solution 6:
The various parts of a human skeleton are:

1. Axial skeleton: This consists of skull, vertebral column, sternum and ribs
2. Appendicular skeleton: It consists of pectoral and pelvic girdles and bones of limbs.

Solution 7:

Solution 8:
On the basis of position, endoskeleton is divided into two main parts:

 Axial skeleton: This consists of skull, vertebral column, sternum and ribs. Human skull has 22 bones of which 8 are present in the cranium and 14 on the face. Brain is present in the cavity called cranium. In the occipital region is an opening called foramen magnum through which spinal cord passes. Cranium has 8 bones which covers the brain from all sides.
 Facial bones: These bones form the face and protect the sensory organs present in the head. It has 14 bones.
Vertebral Column:
It makes the axis of the body and provides support like a pillar. Vertebral column is divided into following five parts:

1.  Cervical Region. It has 7 cervical vertebrae. First vertebra is called atlas, second is axis and rest are called typical cervical vertebrae.
2.  Thoracic Region. It has 12 thoracic vertebrae. Neural spine of these vertebrae is long and pointed, which provdes surface for muscle and attachment.
3. Lumber Region. It has 5 lumber vertebrae.
4.  Sacral Region. It has 5 sacral vertebrae which are permanently fused to each other. These are situated on both halves of pelvic and form a joint with pelvic girdle.
5.  Caudal Region. It has 4 caudal vertebrae. These are also fused to form a triangular structure which is called coccyx.

Sternum and Ribs
Sternum is the bone at the mid-ventral line of the thorax to which most of the ribs are attached at their ventral ends. Ribs are formed by vertebral and sterna part. First seven pairs of ribs are called true ribs. These are joined on one side with sternum and on second side with thorax.
Appendicular skeleton: It consists of limbs, shoulder or pectoral girdle and hip or pelvic girdles and bones of limbs.

1. Bones of the fore arm: Humerus, radius, Ulna, Carpals, Metacarpals, finger bones, etc.
2.  Bones of hind limb: Femur, Tibia, Fibula, Tarsal, Metatarsal, etc.
3.  Pectoral Girdle: In mammals, two halves of pectoral girdle are situated at equal distance from the ribs on the dorsal plane. Each of it is called shoulder bones. Each half of it made up of a triangular flat bone called scapula. From its outer side a projection arises called acromion and has a cavity called glenoid cavity.
4.  Pelvic Girdle: It consists of two similar halves. In each, three bones are found, ilium, ischium and pubis. Pubis bones of both halves are joined and are called pubic sysmphysis. Ilium and ischium form acetabulum cavity in which head of femur articulates by forming ball and socket joint. A hollow space is found between pubis and ischium, which is called obdurate foramen, which provides passage for obturatry artery, vein and nerve.

Solution 9:

Solution 10:

Solution 11:
Importance of pectoral girdle:

1. It provides support to the anterior portion of the body.
2.  Provides surface articulation of fore arms.
3.  Provides surface for muscle attachment.
4.  Provides protection to vital organs like heart and lungs.

Importance of pelvic girdle:

1. Provides surface articulation of hind limbs.
2. Provides surface for joining of muscles.
3.  Provides protection to the uterus.
4. Protects from shocks.

Solution 12:
The place of joining of two or more than two bones is called joint.

Solution 13:
Flexor is a muscle that causes bending of a limb or other part e.g. thigh muscle.
Extensor is the muscle that causes the straightening of a limb or other part. E.g. for extending the foot
Levator is the muscle that raises any part of the body.
Rotator is a muscle that rotates one part on another.

Solution 14:
Axial skeleton: This consists of skull, vertebral column, sternum and ribs. Human skull has 22 bones of which 8 are present in the cranium and 14 on the face. Brain is present in the cavity called cranium. In the occipital region is an opening called foramen magnum through which spinal cord passes. Cranium has 8 bones which covers the brain from all sides.
Facial bones: These bones form the face and protect the sensory organs present in the head. It has 14 bones.
Vertebral Column:
It makes the axis of the body and provides support like a pillar. Vertebral column is divided into following five parts:

1. Cervical Region. It has 7 cervical vertebrae. First vertebra is called atlas, second is axis and rest are called typical cervical vertebrae.
2. Thoracic Region. It has 12 thoracic vertebrae. Neural spine of these vertebrae is long and pointed, which provdes surface for muscle and attachment.
3. Lumber Region. It has 5 lumber vertebrae.
4.  Sacral Region. It has 5 sacral vertebrae which are permanently fused to each other. These are situated on both halves of pelvic and form a joint with pelvic girdle.
5. Caudal Region. It has 4 caudal vertebrae. These are also fused to form a triangular structure which is called coccyx.

 Sternum and Ribs:
Sternum is the bone at the mid-ventral line of the thorax to which most of the ribs are attached at their ventral ends. Ribs are formed by vertebral and sterna part. First seven pairs of ribs are called true ribs. These are joined on one side with sternum and on second side with thorax.
 Appendicular skeleton: It consists of limbs, shoulder or pectoral girdle and hip or pelvic girdles and bones of limbs.

1. Bones of the fore arm: Humerus, radius, Ulna, Carpals, Metacarpals, finger bones, etc.
2.  Bones of hind limb: Femur, Tibia, Fibula, Tarsal, Metatarsal, etc.
3. Pectoral Girdle: In mammals, two halves of pectoral girdle are situated at equal distance from the ribs on the dorsal plane. Each of it is called shoulder bones. Each half of it made up of a triangular flat bone called scapula. From its outer side a projection arises called acromion and has a cavity called glenoid cavity.
4. Pelvic Girdle: It consists of two similar halves. In each, three bones are found, ilium, ischium and pubis. Pubis bones of both halves are joined and are called pubic sysmphysis. Ilium and ischium form acetabulum cavity in which head of femur articulates by forming ball and socket joint. A hollow space is found between pubis and ischium, which is called obdurate foramen, which provides passage for obturatry artery, vein and nerve.

Solution 15:
Forelimbs consists of one humerus (anterior arm bone), one radius and one ulna (posterior arm bones), 8 carpals (wrist bones), 5 metacarpals ( palm bones) and 14 phalanges (finger bones).
Hindlimb consists of one femur bone or thigh bone, one tibia and fibula which are bones of the leg, 8 tarsals (bones of ankle), 5 metatarsals (bones of feet), and 14 phalanges (bones of fingers).

Solution 16:
The three levers found in the human skeleton are:

1. First order levers
2. Second order levers
3. Third order levers

Solution 17:

1. Ball and socket joint
2. Pivot joint

Solution 18:
In a ball and socket joint, the ball of one bone is fitted into the socket of another bone such that the ball can move in the socket. Such a joint always involves a long bone, which can move in all planes. This type of joint is found in pectoral girdle, glenoid cavity, femur and acetabulum of pelvic girdle.

Solution 19:
Forelimbs consists of one humerus (anterior arm bone), one radius and one ulna (posterior arm bones), 8 carpals (wrist bones), 5 metacarpals (palm bones) and 14 phalanges (finger bones).
Hind limb consists of one femur bone or thigh bone, one tibia and fibula which are bones of the leg, 8 tarsal (bones of ankle), 5 metatarsals (bones of feet), and 14 phalanges (bones of fingers).

Solution 20:
Biceps muscles first contract to bend the arm, following which the triceps muscles act to straighten the arm. Thus act in opposite ways and are antagonistic muscles, since they counteract each other’s action. The muscles of biceps are called flexor muscle while that of the triceps is the extensor muscle. This whole coordination of muscular action is under the nerve impulse and brain control.

Solution 21:
Muscles which counteract each other’s actions are known as antagonistic muscles. Biceps and triceps are two such muscles.

Solution 22:
Biceps cause bending of a limb or other part. Triceps cause straightening of a limb or other part.

Solution 23:
Striped, Unstriped and cardiac muscles.

Solution 24:

1.  Synovial joint is a movable joint present between the adjoining bones which can move independently. The articulating surfaces of the two bones are covered with articular cartilage. The joint is covered with a synovial membrane which secretes synovial fluid for lubrication.
2.  These are found in elbow joint, knee joint, femur and pelvic girdle, etc.
3. The cartilages cover the ends of the adjoining bones. They function to absorb shock and reduce friction during movement.
4. 1 and 5 -epiphyseal bone
   2- synovial cavity
   3- synovial fluid
   4- synovial membrane

Solution 25:

1. (a)  Scapula;
2. Shoulder joint;
3.  Humerus;
4. Bicep;
5. Tricep;
6. Radius;
7. Tricep
8. Elbow Joint;
9. Ulna.

(b) Bicep muscles and triceps are antagonistic muscles.
(c) Bicep muscles.
(d) Shoulder bones.
(e) Ball and socket joint.

PAGE NO:163

Solution 26:

1. (d) all the above
2. (c) 24
3. (b) 7
4. (a) Parietals of skull
5. (d) stapes
6. (b) Cranium
7. (c) It allows movement in all directions.

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Frank ICSE Solutions for Class 9 Biology – Digestive System

 

PAGE NO:151

Solution 1:
Nutrition can be defined as the process which involves the utilization of food by an animal to obtain energy for growth and development. There are two types of nutrition – autotrophic and heterotrophic.

Solution 2:

1.  Autotrophs: These are the organisms which prepare organic food in their body from simple inorganic materials like carbon dioxide, water, etc. Example – green plants and certain protests.
2. Heterotrophs: The organisms which cannot prepare their own food and depends on ready-made food synthesized by green plants are called heterotrophs. Examples – animals and human beings.
3. Carnivores: The organisms which feed upon other animals and animal products. Examples – tiger, lion, cat, etc.
4. Omnivores: The organisms which feed on all kinds of plant and animal food are called omnivores. Examples – Cockroach and human beings.
5. Herbivores: The organisms that feed on plants only are termed as herbivores. Examples – sheep, cow, goat, etc.

Solution 3:

1.  Parasites are the organisms that live in or on the body of another organism called host, and obtain nourishment from its body whereas saprophyte is an organism that absorbs soluble organic nutrients from dead and decaying organic matter.
2. Autotroph is an organism which prepares organic food in their body from simple inorganic materials like carbon dioxide, water, etc. whereas heterotroph is an organism which cannot prepare its own food and depends on ready-made food synthesized by green plants.
3. Holozoic nutrition is a nutrition in which animals survive by consuming other organisms whereas saprozoic nutrition is the nutrition in which the animals absorbs soluble organic nutrients from dead and decaying organic matter.
4.  Holophytic nutrition is the nutrition in which organisms prepare organic food in their body from simple inorganic materials like carbon dioxide, water, etc. whereas in holozoic nutrition, the animals survive by consuming other organisms.

Solution 4:
The steps involved in animal nutrition are:

1. Ingestion – It means taking solid or liquid food inside the body.
2. Digestion – It is the breaking down of complex insoluble food components into simple soluble substances.
3.  Absorption – It is the process by which soluble soluble digested food passes from alimentary canal into blood and lymph through intestinal villi.
4. Assimilation – Utilization of absorbed food by different body cells is called assimilation.
5.  Egestion – Elimination of undigested food as faeces is called egestion.

Solution 5:
There are four types of teeth:

1. Incisors – These are used for cutting.
2.  Canines – These teeth are used for tearing.
3.  Premolars – For masticating the food.
4. Molars – For grinding and masticating the food.

Solution 6:

Solution 7:

Solution 8:
(a) False
(b) False
(c) True
(d) False

Solution 9:

Solution 10:

Solution 11:

Solution 12:
Salivary Glands – Three pairs in man and secrete 1000 to 1500 cc saliva per day.
Saliva is slightly acidic and its pH is 6.8.
There are three types of salivary glands:

1.  Parotid glands: It is the largest salivary gland and situated near the ears. It opens into oral cavity by Stenoson’s duct.
2.  Sublingual glands: It is located beneath the tongue. It opens into the floor of oral cavity by duct of Rivinus.
3.  Submadibular or sub-maxillary glands: It is situated at the angles of the lower jaws. It opens inot oral cavity by Whartson’s duct.
   Each gland secret secretes saliva which is transported to the mouth cavity. At the time secrete saliva.

Solution 13:
(a) Lipase
(b) Lungs
(c) Rectum

Solution 14:

Solution 15:

Solution 16:

Solution 17:
(a) Carboxypeptidase
(b) Rennin
(c) Caecum
(d) HCl
(e) Pepsin
(f) Digestion
(g) Protein
(h) Bilirubin

Solution 18:

Solution 19:

1. Stomach – Pepsin
2. Salivary glands – Salivary amylase/Ptyalin
3. Pancreas – Trypsin, Chymotrypsin, Carboxy peptidase, Pancreatic amylase and Pancreatic lipase.
4.  Ileum – Enterokinase, Endokinase, Aminopeptidase and Dipeptidase.

Solution 20:

Frank ICSE Solutions for Class 9 Biology – Nutrition in Man

PAGE NO:138

Solution 1:
Carbohydrates provide energy and warmth to our body.

Solution 2:
Sources of Vitamin C are Lemon and carrot and sources of Vitamin A are Green vegetables and egg yolk.

Solution 3:
Vitamin C

Solution 4:
Pigs and crows

Solution 5:
Carbohydrates

Solution 6:
Roughage

Solution 7:
Assimilation

Solution 8:
Fats

Solution 9:

1. Carnivores are flesh-eating animals that eat other animals. Example – Snakes, Lion, tiger, vulture
2. Omnivores are animals that feed on both animals and plants. Example – crows, certain bears.
3.  Scavenger is any animal that feeds on refuse and other decaying organic matter. Example – vultures, dung beetle.

Solution 10:

Solution 11:
Food is a mixture of nutritive substances which when taken and incorporated into the body tissues provide materials for energy, repair, growth, reproduction, regulation of life processes and resistance to diseases.

Solution 12:
Proteins are used in the synthesis of new protoplasm to be utilized in growth and tissue repair. Hence they are called body building foods.

Solution 13:
(a) Night-blindness
(b) Protein
(c) Vitamin D
(d) Insectivore

Solution 14:
(a) False
(b) True
(c) True
(d) False
(e) True

PAGE NO:139

Solution 15:
Water is necessary for our body because:

1.  Water acts as solvent for many organic and inorganic compounds
2.  Water facilitates the movement of food materials, waste products and other chemical substances in the cytoplasm and circulatory process.
3.  It plays an important role in regulating body temperature and osmotic pressure of the body fluids.
4.  Water serves as good medium for various metabolic reactions.

Solution 16:
The undigested fibrous material present in the food is called roughage. Raw vegetables, and bran are examples of roughage

Solution 17:
(a) energy
(b) glycogen
(c) fatty acid, glycerol
(d) sucrose, maltose

Solution 18:

1. The condition where people become weak and sick due to insufficient and unbalanced diet is referred to as malnutrition.
2.  Saprozoic nutrition refers to nutrition in which animals feed on dead or decaying matter.
3. Vitamins are organic compounds regularly required in minute quantities in the diet for normal metabolism, health and growth.

Solution 19:
(a) Milk
(b) Sugarcane
(c) Plants
(d) Yellow and green vegetables

Solution 20:

1. Kwashiorkor develops in children whose diet is deficient in proteins even if sufficient carbohydrates and fats are consumed. This disease is common among infants and children up to 3 years old. The symptoms of Kwashiorkor include reduced body weight, slurred growth, protruding belly and thin legs.
2.  Marasmus is a form of prolonged protein energy malnutrition. It affects infants under one year of age. The symptoms of Marasmus include irreversible muscle degeneration, dry, wrinkled skin, prominent ribs and thin legs.

Solution 21:

1.  Deficiency of iron leads to anaemia.
2.  Deficiency of iodine leads to goitre.

Solution 22:

1. (a) 500 gm
2. (d) food
3. (b) rice
4. (b) Carrot
5. (a) A, D and E
6. (d) K
7. (c) Protein
8. (a) C

Frank ICSE Solutions for Class 9 Biology – Bacteria and Fungi Their Importance

PAGE NO:127

Solution 1:

1.  Bacteria are a large group of unicellular, prokaryotic microorganisms.
2.  The bacteria which do not get stained with crystal violet and iodine solution are called gram negative bacteria while those bacteria which get stained with crystal violet and iodine solution are called gram positive bacteria.

Solution 2:

1. Bacteria shows the presence of cell wall, hence they are included under plants.
2.  Spore formation helps bacteria to survive during adverse environmental conditions. Hence it is a survival technique.
3.  Bacteria as friends :
   Bacteria are useful to us in many ways like producing antibiotics, forming curd and cheese, tanning leather, producing various industrial products, nitrogen fixation, digesting cellulose etc.
   Bacteria as foes:
   They are harmful in many ways like causing diseases, bio-weapons , food spoilage etc.
4. Yeast is used in breweries since the fermentation activity of yeast produces different types of beverages like wine, beer, alcohol toddy etc. In bakeries, when yeast is added to the flour its fermentation results in the production of carbon dioxide which produces soft bread and other bakery products.

Solution 3:

Solution 4:

Solution 5:

PAGE NO:128

Solution 6:

Solution 7:
(a) Penicillium notatum
(b) Aspergillus fumigatus
(c) Candida albicans
(d) Aspergillus

Solution 8:
(a) chitin
(b) saprophytic
(c) obligate aerobes
(d) Agaricus campestris

Solution 9:

Solution 10:
Fungi are cooked like vegetables or used in pulao or prepared as soups. Some common edible fungi are Agaricus, Ramaria, Clavaria, Morchella.
Also yeast is used in preparing idli and dosa from a mixture of powdered rice and dal.

Solution 11:
Yes. Many types of antibiotics are obtained from fungi which are used in medical sciences. Today about 25 types of antibiotics are commercially produced from moulds.
For example: Penicillin is obtained from the fungus Penicillium notatum.
Griseofulvin is extracted from the fungus Penicillium griseofulvum.

Solution 12:

Solution 13:

1. (b) Leeuwenhoek
2. (a) bacteria
3. (b) Bacillus
4. (a) Tuberculosis
5. (d) Rhizobium
6. (b) Lactobacillus
7. (d) Agaricus
8.  (a) ethyl alcohol

BiologyChemistryPhysicsMaths

Frank ICSE Solutions for Class 9 Biology – Diversity of Life and Classification

PAGE NO:117

Solution 1:
Diversity refers to the variety of living organisms found within a given ecosystem, biome, or on an entire planet.

Solution 2:
The method of arranging organisms into series of groups on the basis of similarities and differences is called classification.
Classification is important in the following ways:

1.  It makes the study of a wide variety of organisms easy.
2.  It gives us an overall picture of all the life-forms.
3. It helps us to understand the interrelationships among different groups of organisms.
4. It forms a base for the development of other biological sciences.

Solution 3:

Solution 4:
Taxonomy is the study of the theory, practice and rules of classification of living and extinct organisms.

Solution 5:
The five kingdom system of classification was proposed by R. H. Whittaker in 1969. This classification is based on the following four facts:

• Complexity of cell structure
•  Methods of nutrition (autotrophic or heterotrophic)
• Complexity of body organization.
•  Phylogenetic relationships.

The five kingdoms in this system are:

1. Monera – It includes all the prokaryotes like bacteria and cyanobacteria. They are important decomposers.
2.  Protista – It includes the aquatic, eukaryotic, acellular organisms like protozoans.
3. Fungi – This kingdom includes moulds, mushrooms and yeasts.
4. Plantae – It includes all the coloured, multicellular, eukaryotes with cell walls.
5.  Animalia – These are multicellular eukaryotes lacking cell wall and showing heterotrophic nutrition.

Solution 6:
Important characters of five kingdom are:
 Characters of kingdom Monera are:

1. It contains acellular organisms, ranging in size between 0.15  to 2.0 .
2.  They are prokaryotes, lacking a well-defined nucleus .
3. They usually lack chlorophyll and hence are parasites or saprophytes.
4. Reproduction occurs by binary fission or budding in bacteria.
   Example – Actinomycetes, bacteria, cyanobacteria.

Characters of kingdom Protista are:

1.  They are aquatic, unicellular organisms.
2. They have eukaryotic cells with well-defined nucleus and organelles.
3. They show autotrophic or heterotrophic mode of nutrition.
4. Some protists are parasites and few are decomposers too.
   Example – Euglena, Ameoba, Paramoecium.

 Characters of kingdom Fungi:

1.  They may be unicellular or multicellular.
2. They have heterotrophic nutrition and mostly they are saprophytes.
3. Their body is made up of mycelium, a filament of which is called hypha.
4.  Their cell wall is made up of chitin.
   Example – Aspergillus, Agaricus, Penicillium.

 Characters of kingdom Plantae:

1. They are multicellular, eukaryotic organisms.
2.  The cell membrane is surrounded by a thick cell wall of cellulose.
3. Except a few aquatic life forms, plants are non-motile.
4.  They have different modes of nutrition: autotrophic, parasitic even
   insectivorous.
   Example – Mango, Cycas, Fern, Moss.

 Characters of kingdom Animalia:

1.  They are multicellular, eukaryotic organisms without cell wall.
2. They show heterotrophic mode of nutrition.
3. They can retract or expand with the help of muscles.
4.  They are consumers in-between producers and decomposers.
   Example – Fish, Frog, Earthworm, Man.

Solution 7:
The kingdom Plantae has been divided into following groups:
Thallophyta 

•  They are consists of red, green and brown algae.
•  Algae are of universal occurrence.
•  Their body ranges from unicellular to multicellular colonies, filaments or sheets of cells.
• Vascular tissues are absent.
•  Nutrition is generally autotrophic (through photosynthesis).
• Reproduction is vegetative or sexual.

 Bryophyta

•  It consists of liverworts and mosses.
• They are terrestrial, found in damp, shady places.
•  Their life cycle has a long gametophytic phase and a short sporophytic phase.
• Liverworts have prostrate thalloid gametophytic body, but mosses have erect body.
• True roots are absent, but rhizoids presents.
•  Vascular tissues are absent.
•  Nutrition is generally autotrophic (through photosynthesis).
•  Reproduction is vegetative or sexual.

 Pteridophyta 

• They include ferns, horse-tails and club mosses.
• They occur mainly in cool, shady and moist places.
• They are mostly terrestrial.
• They are perennial herbs with stem in the form of rhizome.
•  Fibrous roots present.
• Their life cycle has a gametophytic phase and a short sporophytic phase.
•  Vascular tissues are present.
•  Nutrition is generally autotrophic (through photosynthesis).
•  Reproduction is vegetative or sexual.

 Spermatophyta 

•  They are the most successful terrestrial plants having seeds.
•  They produce seeds (fertilized ovules).
• They are divided into two groups –

1.  Gymnosperms -They bear naked seeds and lack flowers.
   Examples: Pine, Cycas
2. Angiosperms – They produce seeds enclosed in ovary and flowers
   are present.
   Examples: Rose, Grass

Solution 8:

Solution 9:

Solution 10:
The various classes of Chordata are:

1. Pisces – Labeo (Rohu), Scoliodon (Dog fish)
2. Amphibia – Rana (Frog), Hyla (Tree frog )
3.  Reptilia – Kanchuga (Tortoise), Naja naja ( Cobra)
4.  Aves – Columba (Pigeon), Pavo (Peacock)
5. Mammalia – Elephas ( Elephant), Funambulas (Squirrel)

Solution 11:

Solution 12:
Characters of mammals are:

1. The females of this class are provided with mammary glands which produces milk to feed the young one.
2. Body usually covered with hair, spines, scales, nail, hoof or horn.
3.  External ear or pinna is well-developed.
4. They are warm-blooded.

PAGE NO:118

Solution 13:
(a) Starfish belongs to phylum Echinodermata.
Two characters of starfish are:

1. Spines found on the body which is covered by calcareous plates.
2.  Body is star shaped with five radiating areas called ambulacra with inter-ambulacra in between.

(b) Whale belongs to phylum Chordata.
Two characters of whale are:

1. They are warm blooded marine animals.
2. Heart is completely four-chambered.

(c) Jelly fish belongs to phylum Coelenterata.
Two characters of jelly fish are:

1.  Body diploblastic having outer epidermis and inner gastrodermis with gelatinous mesoglea.
2. Tentacles are present around the mouth.

(d) Cockroach belongs to phylum Arthropoda.
Two characters of cockroach are:

1.  They have jointed legs.
2. Their exoskeleton is made up of chitinous cuticle which is shed from time to time.

Solution 14:

Solution 15:
Bryophyta – Liverwort and Moss.
Pteridophyta – Fern and Horsetail.

Solution 16:
Antedon (Sea lily) and Asterias (Star fish ).

Solution 17:
Whale

Solution 18:
Cockroach, crab

Solution 19:
Frog

Solution 20:
Echidna

Solution 21:
Earthworm – Pheretima posthuma and
Roundworm – Ascaris

Solution 22:

Solution 23:
(a) Arthropoda
(b) Porifera
(c) Mollusca

Solution 24:
(a) Protozoa
(b) Mollusca
(c) Annelida

Solution 25:
(a) Asterias (Star fish ), Echinus (Sea-urchin)
(b) Scoliodon (Dog fish), Labeo (Rohu)
(c) Fasciola ( Liver fluke), Taenia solium (Tapeworm)
(d) Ascaris ( Roundworm), Wuchereria (Filarial worm )
(e) Pheretima (Earthworm), Hirudinaria ( Leech )
(f) Palemon (Prawn), Periplaneta (Cockroach)

Solution 26:
(a) Annelida
(b) Coelenterata
(c) Arthropoda
(d) Echinodermata

Solution 27:
(a) Flame cells
(b) Nemathelminthes
(c) Annelida
(d) Porifera
(e) Chordata

Solution 28:

1. (a) three pairs of legs are present.
2. (a) coelentrata
3. (c) octopus
4. (c) paramoecium
5. (c) hippocampus
6. (a) Scorpion
7. (b) for five kingdom classification
8.  (a) prokaryotic and multicellular eukaryotic cell
9.  (d) plant
10. (d) C. Linnaeus
11. (c) Carolus Linnaeus

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Frank ICSE Solutions for Class 9 Physics – Light

PAGE NO: 261
Solution 1:
Convex mirror has a wider field of view.

Solution 2:
Convex mirror always produces an erect image of the object.

Solution 3:
Convex mirror is used in vehicles to see the traffic on rear side.

Solution 4:
We will use convex mirror to see an enlarged image of our face.

Solution 5:
Image of object placed at a long distance in front of a convex mirror is formed at principal focus. Radius of curvature of convex mirror is 20 cm.
Focal length of convex mirror = radius of curvature/2.
Focal length of convex mirror = 20/2 = 10 cm.
So image will form at principal focus 10 cm away from pole.

Solution 6:
Concave mirror can produce real and diminished image of the object.

Solution 7:
The distance of the principal focus from the pole of the mirror is called the focal length of the mirror.

Solution 8:
The mirror having +20 cm as its focal length is a convex mirror because focal length is taken positive only in case of convex mirror.

Solution 9:
The focal length of plane mirror is infinity.

Solution 10:
The mirror having -15 cm as its focal length is a concave mirror because focal length is taken negative only in case of concave mirror.

Solution 11:
Principal axis is the straight line passing through the pole and the centre of curvature.

Solution 12:
Linear magnification is defined as the ratio of the height of the image to the height of the object. It is taken to be positive for an image to be virtual and erect and negative when image is real and inverted.
Magnification = height of image / height of object.

Solution 13:
Pole is the centre of the reflecting surface, in this case spherical mirror.

Solution 14:
Centre of curvature is the centre of the imaginary sphere to which the mirror belongs.

Solution 15:
Three characteristics of light are:-

• Light waves can travel through vacuum.
• Light waves are transverse waves.
• The velocity of light in vacuum is 3 x 10⁸ m/s.

Solution 16:
Three distinctions between light and sound waves are

• Light waves can travel through vacuum while sound waves cannot.
• Light waves are transverse waves while sound waves are longitudinal waves.
• The velocity of light in air is 3 x 10⁸ m/s while the speed of light in air is just about 330 m/s.

Solution 17:

• When position of object is at infinity, concave mirror forms a point and Real image at Focus point.
• When position of object is beyond C, concave mirror forms a Diminished, Real and inverted image between F and C.
• When position of object is at C, concave mirror forms a Magnified, Real and inverted image at C.

Solution 18:
Image formed by a convex mirror is always Diminished, Virtual and Erect.

Solution 19:
Concave mirrors are used in reflecting microscope, in shaving and make up glasses and in ophthalmoscope.

Solution 20:

• The distance from the pole in the direction of incident ray is taken positive.
• The distance from the pole in the direction opposite to the incident ray is taken negative.

Solution 21:
Mirror formula is the relation between the focal length f of the mirror, the distance u of the object from the pole of the mirror, and the distance v of the image from the pole.
Mirror formula is
1/v +1/u = 1/f.
Linear magnification is defined as the ratio of the height of the image to the height of the object. It is taken to be positive for an image to be virtual and erect and negative when image is real and inverted.
Magnification = height of image / height of object.

Solution 22:
Mirror formula is the relation between the focal length f of the mirror, the distance u of the object from the pole of the mirror, and the distance v of the image from the pole.
Mirror formula is
1/v +1/u = 1/f.
Size of body = 1.5 m.
Magnification of body = 1.5.
Magnification = height of image / height of object.
Height of image = magnification x height of object.
Height of image = 1.5 x 1.5= 2.25 m.

Solution 23:
Linear magnification is defined as the ratio of the height of the image to the height of the object. It is taken to be positive for an image to be virtual and erect and negative when image is real and inverted.
Magnification produced by concave mirror is:
Magnification = height of image / height of object.
It is a pure ratio and does not have any units.

Solution 24:

Solution 25:
A smooth and polished surface causes regular reflection while a rough and unpolished surface causes irregular reflection.

Solution 26:
When rays of light fall on a surface, they are turned back into the same medium in accordance with some definite laws. This process is known as reflection.
Reflection obeys following two laws

• The incident ray, the reflected ray, and the normal at the point of incidence, all lie in the same plane.
• The angle of incidence and the angle of reflection are always equal.

Solution 27:
You can distinguish between plane mirror, a concave mirror, and a convex mirror without touching them. When you look into these mirrors by bringing your face close to each mirror, they will produce an image of your face of different types.

• A plane mirror will produce an image of the same size as your face.
• A concave mirror will produce a magnified image of your face.
• A convex mirror will produce Diminished image of your face.

Solution 28:
You can distinguish between a concave mirror and a convex mirror without touching them. When you look into these mirrors by bringing your face close to each mirror, they will produce an image of your face of different types.

• A concave mirror will produce a magnified image of your face.
• A convex mirror will produce Diminished image of your face.

PAGE NO : 262
Solution 29:

Solution 30:
Uses of concave mirror:

• Concave mirrors are used in reflecting microscope
• Concave mirrors are used in shaving and make up glasses.
  Uses of convex mirror: Convex mirrors are used as a rear view mirror in automobiles as it provides a wider view of following traffic.

Solution 31:
We can see the reflection of our face on a polished table top because a regular reflection occurs in case of a polished surface while on a unpolished table top irregular reflection occurs which make image of our face unclear.

Solution 32:

• The angle of incidence is the angle made by the incident ray with the plane mirror. {FALSE}
  Correct statement is the angle of incidence is the angle made by the incident ray with the normal to the surface of plane mirror.
• If a ray of light incident on a plane mirror is such that it makes an angle of 30° with the normal, then the angle of reflection is 60°.{FALSE}
  Correct statement is if a ray of light incident on a plane mirror is such that it makes an angle of 30° with the normal, then the angle of reflection is 30°.
• If the incident ray makes an angle of X° with the normal, then the angle between the incident ray and reflected ray is 2X°. {TRUE}
• The image formed in a plane mirror is real, erect and same size as that of the object. {FALSE}
  Correct statement is the image formed in a plane mirror is virtual, erect and same size as that of the object.

Solution 33:

Solution 34:

Solution 35:
The image formed by a plane mirror is erect and virtual. It is a laterally inverted image. The image formed is of the same size as that of the object. Also, the image and the object are equidistant from the mirror.

Solution 36:

Solution 37:
Given, distance of boy from the mirror = 3 m

• Distance of image from mirror = distance of boy from the mirror = 3 m
  Distance between boy and his image = distance of boy from the mirror + distance of image from mirror = 3+3 = 6 m
• Now, distance of boy from the mirror = 4 m
  Distance of image from mirror = 4 m
  Distance between boy and his image = distance of boy from the mirror + distance of image from mirror = 4+4 = 8m.

Solution 38:
Periscope is used to see over the top of an obstacle. It is also used in submarines for observing for movement of ships. It can be used from the trenches for observing the movement on the surface of earth.

PAGE NO : 263
Solution 39:

Solution 40:

• Pole is the centre of the reflecting surface, in this case spherical mirror.
• Centre of curvature is the centre of the imaginary sphere to which the mirror belongs
• Principal focus of a spherical mirror is a point on the principal axis of the mirror, where all the rays travelling parallel to the principal axis and close to it after reflection from the mirror, converge to or appear to diverge from.
• Principal axis is the straight line passing through the pole and the centre of curvature.
• Focus of a concave mirror is a point on the principal axis of the mirror, where all the rays travelling parallel to the principal axis and close to it after reflection from the mirror converge to that point.
• Normal to the surface of a mirror at any point is the straight line at right angle to the tangent drawn at that point.

Solution 41:

Solution 42:

Solution 43:

Solution 44:

Solution 45:

Solution 46:

PAGE NO : 264
Solution 47:

Solution 48:

Solution 49:

Solution 50:

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Frank ICSE Solutions for Class 9 Physics – Light: Spherical Mirrors

PAGE NO: 258
Solution 1:
A spherical mirror is a part of a hollow glass sphere silvered on one side.

Solution 2:

Solution 3:
Focal length = 1/2 of radius of curvature
= 1/2 x 30 = 15cm.

Solution 4:
Focal point is the principal focus of the mirror where a parallel beam of light meets(or appear to meet) after reflection from the mirror.

Solution 5:

Solution 6:

• Pole is the centre of the reflecting surface, in this case spherical mirror.
• Centre of curvature is the centre of the imaginary sphere to which the mirror belongs
• Aperture is the distance between the extreme points on the periphery of the mirror.
• Principal axis is the straight line passing through the pole and the centre of curvature.
• The principle focus of a spherical mirror may be defined as a point on its principle axis where a beam of light parallel to the principle axis converges to or appears to diverge from after reflection from the spherical mirror.

Solution 7:
Convex mirror has a wider field of view.

Solution 8:
Concave mirrors are used in reflecting microscope, in shaving and make up glasses and in ophthalmoscope.

Solution 9:
Convex mirrors are used as a rear view mirror in automobiles as it provides a wider view of following traffic.

Solution 10:
Convex mirror is used in vehicles to see the traffic following it.

Solution 11:
The relationship between the focal length, f and radius of curvature, r is
f = 1/2 x r.

Solution 12:

Solution 13:

Solution 14:
Concave mirror can produce real and diminished image of the object.

Solution 15:
The focal length of plane mirror is infinity.

Solution 16:
The object should be placed between F and P to obtain its magnified and erect image.

Solution 17:

Solution 18:
Linear magnification is defined as the ratio of the height of the image to the height of the object. It is taken to be positive for an image to be virtual and erect and negative when image is real and inverted.
Magnification = height of image / height of object.

Solution 19:
SI unit of focal length is meter.

Solution 20:
The top mirror is convex mirror, the middle mirror is concave mirror and bottom mirror is a plane mirror.

Solution 21:
The mirror having +15 cm as its focal length is a convex mirror because focal length is taken positive only in case of convex mirror.

Solution 22:
The mirror having -20 cm as its focal length is a concave mirror because focal length is taken negative only in case of concave mirror.

Solution 23:
When we look into a plane mirror, the image of our face is virtual because the image cannot be obtained on a screen.

Solution 24:
When an object is brought towards the concave mirror, the position of the image moves away from the mirror and the size increases and it remains inverted but at object position between F and P, the image is virtual, magnified and erect.

Solution 25:

PAGE NO : 259
Solution 26:

Solution 27:

Solution 28:

Solution 29:

Solution 30:

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Frank ICSE Solutions for Class 9 Physics – Light: Reflection of Light

PAGE NO: 245
Solution 1:
Light may be defined as the radiant energy which produces in us the sensation of sight. Light itself is invisible but makes other objects visible.

Solution 2:
Yes, light is a form of energy that produces the sensation of vision in our eyes.

Solution 3:
The velocity of light in vacuum is 3 x 10⁸ m/s.

Solution 4:
Two sources of light are

• Natural, for e.g. Sun
• Artificial, for e.g. Light bulb.

Solution 5:
Four characteristics of light are :-

• Light waves can travel through vacuum
• Light waves are transverse waves
• Wavelength of light waves is short so that their length is measured in centi-microns.
• The velocity of light in vacuum is 3 x 10⁸ m/s.

Solution 6:
The Sun and the stars are the two luminous bodies.

Solution 7:
Two non -luminous bodies are moon, chair.

Solution 8:

Solution 9:
A ray of light is the path along which light travels.

Solution 10:
Three distinctions between light and sound waves are

• Light waves can travel through vacuum while sound waves cannot.
• Light waves are transverse waves while sound waves are longitudinal waves.
• The velocity of light in air is 3 x 10⁸ m/s while the speed of light in air is just about 330 m/s.

PAGE NO : 246
Solution 11:

• A ray of light
• Divergent beam of light
• Divergent beam of light
• Parallel beam of light

Solution 12:
The substance through which light is made to pass is called medium.

Solution 13:
Rectilinear propagation of light is that the light travels along a straight line.

Solution 14:
No, glass is a transparent medium.

Solution 15:
No, no metal is transparent by nature.

Solution 16:

Solution 17:
Waxed paper is the translucent medium among the given substances.

Solution 18:

Solution 19:
Two observations that proves that light travels in a straight line are :-

• Sunlight coming through a hole in a dark room, we can easily see that light travels in a straight line
• Light coming from a laser light, used for presentation, can also be seen to travel in straight line.

Solution 20:
When rays of light fall on a surface, they are turned back into the same medium in accordance with some definite laws. This process is known as reflection.

Solution 21:
A smooth and polished flat surface is the cause of regular surface.

Solution 22:
Reflection obeys following two laws

• The incident ray, the reflected ray, and the normal at the point of incidence, all lie in the same plane.
• The angle of incidence and the angle of reflection are always equal.

Solution 23:
The height of plane mirror should be half of the size of the object to get a full image of the object. So for a man of height 1.6 m tall should use a 0.8m tall plane mirror.

Solution 24:
Rectilinear propagation of light is that the light travels along a straight line.

Solution 25:
Lateral inversion is the reversal of image experienced in a plane mirror. The image is of the same size and equidistant from the object but the left and right sides are transposed.

Solution 26:
Formation of image is the phenomenon based on laws of reflection.

Solution 27:
The principle employed in a periscope is successive reflections from two plane mirrors.

Solution 28:
The point at which the light is incident on the reflecting surface is called the point of incidence.

Solution 29:
Any smooth, highly polished reflecting surface is called mirror.

Solution 30:
A smooth, highly polished plane surface is called plane mirror.

Solution 31:
The angle between the incident ray and the normal to the surface at the point of incidence is called the angle of incidence.

Solution 32:

Solution 33:
Given, angle between incident ray and mirror = 35°

• Angle of incidence = angle of mirror to the normal – angle between incident ray and mirror
  = 90 – 35 = 55°
• Angle of reflection = angle of incidence = 55°
• Total angle turned = angle of incidence + angle of reflection
  = 55 + 55 = 110°
• The angle between incident ray and reflected ray = Angle of incidence + Angle of reflection
  = 55 + 55 = 110°

Solution 34:
Given, distance of boy from the mirror = 3 m

• Distance of image from mirror = distance of boy from the mirror = 3 m
  Distance between boy and his image = distance of boy from the mirror + distance of image from mirror = 3+3 = 6 m
• Now, distance of boy from the mirror = 4 m
  Distance of image from mirror = 4 m
  Distance between boy and his image = distance of boy from the mirror + distance of image from mirror = 4+4 = 8 m.

Solution 35:

PAGE NO : 247
Solution 36:
Two characteristics of image formed by plane mirror are

• Image is erect and virtual
• Image and object are of same size.

Solution 37:

Solution 38:

Solution 39:

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Frank ICSE Solutions for Class 9 Physics – Heat: Transmission of Heat

PAGE NO: 226
Solution 1:
Conduction, convection and radiation are three modes of transfer of heat.

Solution 2:
The process of conduction involves the transmission of heat from the hot end to the cold end from particle to particle of the medium.

Solution 3:
No, conduction is not possible in vacuum.

Solution 4:
Thermal insulation means restriction of transfer of heat by any means.

Solution 5:
Good conductor allow heat to pass through them easily while bad conductor of heat does not allow heat to pass them.

Solution 6:
No, liquids are poor conductors of heat.

Solution 7:

• Metals are the best conductor of heat.
• Gases are the worst conductor of heat.

Solution 8:
Among all the metals, Silver is most conducting.

Solution 9:
Air is most non-conducting.

Solution 10:
No, air is not a good conductor of heat.

Solution 11:
Yes, this is a correct statement. Ebonite and asbestos are worst conductor of heat.

Solution 12:
Cooking utensils are made up of metals because metals are good conductors of heat and they easily allow the heat to pass through them.

Solution 13:
Brick is bad conductor of heat, hence bricks greatly reduce the conduction of heat from outside to the room. In order to ensure better insulation, bricks are made hollow so that air filled between these gaps provides insulation to heat.

Solution 14:
Mercury is good conductor of heat.

Solution 15:
In cold countries, windows have two glass panes and a thin layer of air in between these two glass panes because air is a poor conductor of heat; it obstructs the conduction of heat from the room to the outside.

Solution 16:
Order of increasing heat conductivity:
Air < water< mercury < copper.

Solution 17:

• Water is heated from below because water is heated by process of convection and in process of convection heat always flows in upward direction from downward direction.
• In process of convection heat is transferred from one point to another by actual movement of particles of medium and as particles of solid cannot move so process of convection is not possible in case of solids.
• Conduction is not possible in Vacuum because process of conduction require a material medium for transfer of heat.
• Inside the refrigerator, cooling takes place by convection. The freezing chamber at the top produces cool and heavy air which descends and hot air from below goes up setting convection current. Thus, cooling in a refrigerator is kept near the top.
• As earth surface gets heated by sun rays and due to process of convection the air near earth surface open to sunlight get heated while in shade sun rays does not fall on earth surface so air near that surface would not heat up.

Solution 18:

Solution 19:

PAGE NO : 227
Solution 20:
We receive heat from sun by process of Radiation.

Solution 21:
Radiating power of a surface can be increased by blackening it.

Solution 22:
Heat radiation travels with speed of light and always follows straight path.

Solution 23:
The flask consists of a double walled glass container with vacuum between the walls A and B. The inner side of A and the outer side of B are silvered. It has a narrow mouth which is closed by a non-conducting rubber stopper.
If a hot liquid is placed inside the flask, it cannot lose heat by conduction or convection, as there is no air between the walls. The small amount of heat lost from the liquid by radiation is reflected back into the liquid by silvering of the inner wall A and any radiation striking the outer wall B, is reflected back and prevented from reaching the liquid.

Solution 24:
Green house is a glass house constructed to keep delicate and rare plants that require warmth and protection from weather. It is constructed by panels of glass. The temperature in a green house rises because heat enters the house through the glass but cannot escape out, because the glass reflects the heat back to the inside of the house. This makes glass house warmer than the outside environment.

Solution 25:
Take two sheets of tin plates, one blackened and the other is polished brightly. Fix some drawing pins on the outer side of both sheets using wax. Fix these plates vertically at a very short distance apart. Place a Bunsen burner midway between them. When you light the burner you will observe that the pins from the black painted sheet start dropping while the pins on the polished surface remain in the same position for much longer time.
Thus, we can conclude that black surface is better absorber of heat than the polished one.

Solution 26:

• As convection require medium for transfer of heat so heat loss due to convection can be minimized if the substance is kept away from any material medium.
• Similarly for conduction, as conduction also require medium for transfer of heat so heat loss due to conduction can be minimized if the substance is kept away from any material medium.
• Heat loss due to radiation can be minimized by polishing the surface as polished surfaces radiate less heat.

Solution 27:

• As no material medium surrounds the ball so there is no possibility of losing heat by conduction or convection. The ball will lose heat by Radiation.
• Ball will lose minimum amount of heat if it is polished.
• As loss of heat take place by Radiation and process of radiation does not require any material medium, so there is no role of air in loss of heat.

Solution 28:

• CFC means Chlorofluorocarbons which are produced mainly by refrigeration industries, aerosol cans, coolants, propellants and plastic foams. They cause global warming.
• UV means ultraviolet range of radiations. These are the radiations which are emitted by sun and they enter our atmosphere.
• WHO is World Health Organization which put a check on diseases and global warming etc.

Solution 29:
Green house is a glass house constructed to keep delicate and rare plants that require warmth and protection from weather. It is constructed by panels of glass. The temperature in a green house rises because heat enters the house through the glass but cannot escape out, because the glass reflects the heat back to the inside of the house. This makes glass house warmer than the outside environment. This phenomenon is called green house effect.

Solution 30:
Carbon dioxide, Carbon monoxide, methane are green house gases.

Solution 31:
As fossil fuels are non-renewable sources of energy they are not available again and again if are fully exhausted, so they should not be used extensively.

Solution 32:
Global warming occurs due to the presence of carbon di- oxide, CFCs, methane in the atmosphere. Carbon dioxide acts as a transparent gas to incoming shortwave radiations which the earth re-radiates into space. It therefore traps the outgoing longwave radiations thus warming lower atmosphere of the earth thereby causing global warming.

Solution 33:
Harmful effects of global warming are:

• The atmospheric temperature of earth would increase thereby making it difficult for a living being to survive.
• It would melt down the polar caps thus increasing the size of the ocean and leading to floods, tsunami, etc.
• The increase in temperature would affect climate and rainfall thus affecting flora and fauna.
• Human beings would be vulnerable to diseases as microbes would get warmth to grow.

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