ICSE Class 6 Physics Important Questions Chapter 2 Measurements

Physics ICSE Class 6 Important Questions Chapter 2 Measurements

Practice Questions

Question 1.
What is a unit ?
Answer:
A unit is a known fixed quantity of the same kind used for comparison in measurements of the physical quantities.

Question 2.
Name few earliest tools (traditional units) to measure length.
Answer:
Cubit, handspan, palm and fingers.

Question 3.
What do the following systems of measurement stand for –

1. FPS
2. MKS
3. CGS
4. SI

Answer:

1. FPS – foot – pound – second
2. MKS – metre – kilogram – second
3. CGS – centimetre – gram – second
4. SI – International System of Units

Question 4.
Write the units of measurement used in –

1. MKS system
2. CGS system and
3. SI system

Answer:

Question 5.
Define length. Name some commonly used devices to measure length.
Answer:
Length is defined as the straight-line distance between two points. Devices commonly used to measure length are a ruler, a metre rod and a measuring tape.

Question 6.
How should we use the ruler correctly ?
Answer:

• We should avoid using the ends of a ruler as they chip or break with time.
• Always place the ruler parallel to the length you need to measure and as near as possible to the object.
• Your eye should be positioned in line with the mark you are reading or else parallax error can arise.

Question 7.
What is a plane figure ? Give few examples with the formula to find their area.
Answer:
Any flat, closed figure that can be drawn on a plane surface is called a plane figure. Examples :

• Square : Formula for area = side x side
• Rectangle : Formula for area = length x breadth
• Triangle : Formula for area = \(\frac {π}{2}\) x Base x Height

Question 8.
Give SI unit of measurement for –

1. area
2. volume
3. temperature

Answer:

1. square metre (m²)
2. cubic metre (m³)
3. kelvin (K)

Question 9.
Convert the following units –
(i) 1 m² = ………… cm³
Answer:
1 m²= 10,000 cm²

(ii) 1 L = …………. cm³
Answer:
1 L = 1000 cm³

(iii) 1000 mg = g
Answer:
1000 mg = 1 g

(iv) 1 quintal = kg
Answer:
1 quintal = 100 kg

(v) 1000 years = millenium
Answer:
1000 years = 1 millenium.

Question 10.
Name few devices used to measure mass.
Answer:
Beam balance, spring balance physical balance, electronic weighing machine.

Question 11.
What do you mean by time interval ?
Answer:
Time interval is a definite duration of time between two given instants.

Question 12.
Name two types of spring balances.
Answer:

• Extension spring balance
• Compression spring balance

Question 13.
Name few traditional devices of time measurement.
Answer:
Sundial, water clock, candle clock, sand clock.

Question 14.
Why do we give few jerks to the thermometer before measuring our body temperature ?
Answer:
It is to drop the mercury level below the 35°C mark.

Question 15.
Which body in India is responsible for maintaining the accuracy of weighing and measuring instruments ?
Answer:
Department of Legal Metrology.

Question 16.
Fill in the blanks.
(i) The branch of science which deals with measurement is called as …………
Answer:
The branch of science which deals with measurement is called as metrology.

(ii) Any quantity that can be measured is called a …………. quantity.
Answer:
Any quantity that can be measured is called a physical quantity.

(iii) The measurement of a physical quantity consists of two parts, the ………….. and the …………
Answer:
The measurement of a physical quantity consists of two parts, the magnitude and the unit.

(iv) The word inch comes from the Latin word ‘uncia’meaning …………. part.
Answer:
The word inch comes from the Latin word ‘uncia’meaning one-twelfth part.

(v) The word metre is derived from the Greek word …………… which means a measure.
Answer:
The word metre is derived from the Greek word metron which means a measure.

(vi) ………….. are used to measure the length of curves surfaces and also long lengths of several metres.
Answer:
Measuring tapes are used to measure the length of curves surfaces and also long lengths of several metres.

(vii) Formula to find, volume of cube is …………….
Answer:
Formula to find volume of cube is (side)3 or side x side x ‘ side

(viii) While reading the volume of a liquid in a measuring cylinder, you must ensure that the eye is in …………. line
with the level of the liquid.
Answer:
While reading the volume of a liquid in a measuring cylinder, you must ensure that the eye is in horizontal line with the level of the liquid.

(ix) Electronic weighing machines are the modified version of the …………… spring balance.
Answer:
Electronic weighing machines are the modified version of the Formula to find volume of cube is compression spring balance.

(x) …………….. clocks usually have a circular dial with a scale of 12 hours and two or three hands.
Answer:
Analogue clocks usually have a circular dial with a scale of 12 hours and two or three hands.

(xi) A …………….. clock directly displays the time as numbers.
Answer:
A Digital clock directly displays the time as numbers.

(xii) Maximum and minimum thermometer is also known as …………… thermometer.
Answer:
Maximum and minimum thermometer is also known as Six’s thermometer.

(xiii) …………….. is a number that gives a general idea of the value of a group.
Answer:
Average is a number that gives a general idea of the value of a group.

More Importance Questions

A. Write True of False.

Question 1.
A full stop is never put at the end of a symbol except if . it occurs at the end of a sentence.
Answer:
True

Question 2.
The unit in words is always written in upper case letters.
Answer:
False.
Correct: The unit in words is always written in lower case letters.

Question 3.
Symbols of some units can be written in plural.
Answer;
False.
Correct : Symbols of units can never be written in plural.

Question 4.
There are seven base units in the SI system
Answer:
True

Question 5.
If a unit is named after a person, the unit is written in its full form in upper case letters.
Answer:
False.
Correct: If a unit is named after a person, the unit is written in its full form in lower case letters.

B. Fill in the blanks.

Question 1.
1 metre = 1000 millimetres
2. 1 kilometre = 1000 metres
3. 1 hectometre = 1000 decimetres
4. 1 decametre = 100 decimetres
5. 1 decimetre = 100 millimetres

C. Write the formulae for each of the following.

1. Area of a triangle = \(\frac {1}{2}\) Base x Height
2. Area of a square – Length x Length/(side)²
3. Volume of a cube – (side)³
4. Volume of a cylinder = π x(Radius)² x Height
5. Area of a rectangle = Length .x Breadth

D. Tick the most appropriate answer.

Question 1.
The SI unit of volume is …………
a. m³.
b. cm^3.
c. km³.
d. litres.
Answer:
a. m³.

Question 2.
Areas of irregular surfaces are measured by using ……………
a. a drawing paper,
b. a graph paper.
c. a tracing paper.
d. a carbon paper
Answer:
b. a graph paper.

Question 3.
The distance between ……………
a. centimetres,
d. decametres
c. kilometres.
d. decametres
Answer:
c. kilometres.

Question 4.
Pure water boils at ………………..
a. 100°C
b. 101°C
c. 102°C
d. 100.1°C
Answer:
a. 100°C

Question 5.
The unit of absolute temperature is
a. k.
b. °K
c. °K
d. K
Answer:
d. K

E. Fill in the blanks.

Question 1.
A …………. thermometer is used to record the highest and the lowest temperature of a place.
Answer:
maximum and minimum

Question 2.
The …………. of a cylinder is the curved boundary of the cylinder.
Answer:
mouth

Question 3.
The SI unit .of ………… is second.
Answer:
time

Question 4.
The lower fixed point of a standard thermometer is the melting point of ……………
Answer:
ice

Question 5.
The capillary of the clinical thermometer has a slight bend called the ………….
Answer:
kink

F. Match the following.

Column A	Column B
1. MillIgram	a. Length
2. Millilitre	b. Mass
3. Millimetre	c. Time
4. Millisecond	d. Volumee

Answer:

Column A	Column B
1. MillIgram	b. Mass
2. Millilitre	d. Volume
3. Millimetre	a. Length
4. Millisecond	c. Time

G. State if the following statements are true or false. Correct the statement if it is false.

Question 1.
One metre is defined as the length between two marks on a platinum-iridium bar kept at room temperature at the International Bureau of Weights and Measures at Sevres near Paris in France.
Answer:
False.
Correct : One metre is defined as the length between two marks on a platinum-iridium bar kept at 0°C at the International Bureau of Weights and Measures at Sevres near Paris in France.

Question 2.
The circumference of a cylinder can be measured with a measuring tape.
Answer:
True

Question 3.
The perimeter of a two dimensional figure is the sum of the lengths of all the sides.
Answer:
True

Question 4.
1 kilogram is a hundred quintal.
Answer:
False. Correct: 1 quintal is a hundred kilograms.

Question 5.
The inner tube of the thermometer is called the stem.
Answer:
False.
Correct : The inner tube of the thermometer is called the bore.

H. Give reasons for the following.

Question 1.
Before using, a clinical thermometer is given jerks.
Answer:
Before using a clinical thermometer, we have to jerk it two to three times to ensure that the mercury level drops below the 35°C mark.

Question 2.
A 24-hour clock is a better system of reading time.
Answer:
Services such as railways and air lines, that operate throughout the day, use 24-hour clock in order to avoid confusion. In this system, time is expressed as the number of hours and minutes that have passed since midnight.

Question 3.
The capillary of a clinical thermometer has a kink.
Answer:
The kink in the clinical thermometer ensures that the mercury does not move back into the bulb when the thermometer is taken out of person’s mouth. This gives us time to take the reading after removing the thermometer. After taking reading, mercury can be made to return to the bulb by giving jerk to the thermometer.

Question 4.
It is necessary to have a universally accepted system of measurement.
Answer:
Yes, it is necessaiy to have a universally accepted system of measurements so that there is no variation and is same for all persons at all places and times.

3. Name the instrument used to compare mass.
Answer:
A simple beam balance is used to compare mass.

4. Name three different units of temperature.
Answer:
Three units of temperature are :-
Celsius (°C), Fahrenheit (°F) and kelvin (K).

Question 5.
Write the characteristics of standard units,
Answer:
Characteristics of a standard units :-

• The units should be precisely defined and have same value every where.
• The units should have a convenient size. e.g. cm.
• The system of units should be acceptable everywhere.

I. Answer in detail.

Question 1.
State the common rules for writing units.
Answer:
Common rules for writing units :-
1. If a unit is derived from the name of a person, then the unit in its full form will be written in lower case of alphabets (small letters) – For example kelvin, newton.
2. When we write the symbol of a unit derived from the name of a person, we use upper case alphabet (Capital letter) e.g. K., for kelvin W for watt, N for newton and J for Joule.
3. When we writes units which are not named after persons, the units as well as the symbols are written in lower case letters e. g. metre or m gram or g.
4. The plural form of a unit is used when it is written in full. e.g. 5 metres or 5m but not 5ms.
5. The symbols of prefixes are written in small letters e.g. kilo is k, kilometre is km.
6.  A full stop is never put at the end of a symbol except if it occurs at the end of a sentence.

Question 2.
Describe an experiment to measure the volume of an irregular solid.
Answer:
Take a string, a small stone (as an irregular solid), a measuring cylinder and some water. Pour some water in the measuring cylinder and read its level from the scale on the container. Now tie the string around the stone and lower it into the I cylinder. It should be completely immersed in water. The water rises up. Note the reading.
Intial reading of water level = 50 ml (say)
Final reading of water level = 80 ml (say)
Hence, the volume of the stone = 80 – 50 = 30 ml

Question 4.
Write the construction of a maximum and minimum thermometer and state its use.
Answer:
Construction of maximum and minimum thermometer : It consists of U-shaped capillary tube with two separate temperature readings, one for the maximum temperature and one for the minimum temperature. There are bulbs at the top of each arm of U-shaped tube. The one at the top of minimum reading scale contains alcohol and the other contains a vacuum or low pressure alcohol vapour.

In the bend of the U – tube mercuiy is filled, which is pushed around the tube by the expansion and contraction of the alcohol in the first bulb. Use It is used to measure maximum and minimum temperature of a place on a given day by meteorologists.

Question 5.
When are approximations necessary in daily life and when should they be avoided ?
Answer:
An approximation or estimation, is an educated guess, made out of experience, of measurement of a physical quantity, e.g. we use approximations in many places such as, in cooking, when we are to add salt and spices to bring flavour. They should be avoided while measuring length, mass and time. Averages can be taken.

Question 6.
How can you avoid being cheated when making purchases from your local market ?
Answer:
Always remember that :
(a) a correct beam balance is not riveted or welded at the handle.
(b) The two arms of the balance should be equal.
(c) The pans should also be equal in weights. Make sure that there is lead in hole of the weight.
(d) Make sure the measuring rod should have arrow marks at its ends.
(e) Measuring cans bottom should be flat.

Question 7.
What is parallax error and how can it be avoided ?
Answer:
Parallax error :- An error in reading the measurements which arises due to the wrong position of the eye is called parallax error, e.g. While reading the volume of a liquid from a measuring container, if your eye is not in the line with the level of liquid, it will less or excess volume. This is known as parallex error. It can be avoided by keeping your eye in line with the level of the mark we are reading.

Question 8.
Write the main features of the 24-hour clock system.
Answer:
Features of the 24-hour clock system :-
1. In this system, AM and PM are not used, in order to avoid confusion.
2. Time is shown by 4 digits. The first two digits indicate the number of hours, and the next two digits indicate the number of minutes, e.g. 2:30AM as 0230 and 9.30PM as 2130.

Question 9.
Describe the precautions that must be taken during measurement of length.
Answer:
Precautions to take during measuring length :

• Avoid using the ends of a scale. Due to improper handling scales are chipped at the edges.
• Place the scale correctly. Place the scale parallel to the length you are measuring.
• Check accuracy of reading and human error. Place your eye correctly while taking measurement.

J. Short Answer Questions :

Question 1.
What is measurement ?
Answer:
Measurement: Measurement is a process of comparing an unknown quantity with a known fixed quantity of the same kind.

Question 2.
What is a standard unit ?
Answer:
Standard unit : The units that are used to measure standard quantities are called standard units.

Question 3.
What are derived units ?
Answer:
Derived units : The units which are derived from standard units are called derived units e.g. area, volume etc.

Question 4.
What are S.I. units of mass, length and time ?
Answer:
S.I. units of mass, length and time : Kilogram, metre and second.

Question 5.
How many quintals are there in one metric tonne ?
Answer:
1 metric tonne =10 quintals.

Question 6.
Which institution in India maintains standards of S.I. units.
Answer:
The National Physical Laboratory, New Delhi.

Question 7.
Change the following lengths as indicated.
(a) 1.0 km = ……….. m
(b) 3.6 km = ……….. m
(c) 3 m = ……….. m
(d) 4.2 m = ……….. m
(e) 20.0 cm = ……….. m
(f) 152 mm = ……….. m
Answer:
(a) 1.0 km = 1000 m
(b) 3.6 km = 3600m
(c) 3 m = 300 cm
(d) 4.2 m = 420 m
(e) 20.0 cm = 200 mm
(f) 152 mm = 15.2 m

K. Long Answer Questions :

Question 1.
Why are standard units used in measurements ?
Answer:
Standard units : To maintain uniformity in measurement, scientists, from all over the world accepted some of the units as standard units e.g. M.K.S. (Metre, kilogram, second) for mass, length and time.

Question 2.
Why is a ruler more useful than a hand-span for measuring lengths ?
Answer:
Earlier the length was measured by hand span or a cubit, which is not accurate, which varies from man to man. The system was inconvenient as well as inaccurate. To avoid confusion, scientists evolved rulers. Rulers are marked with standard units of measurement but hand- spans are not.

Question 3.
What are fundamental quantities ? Name any three fundamental quantities.
Ans. Fundamental quantities: The quantities which do not depend on other quantities are known as fundamental quantities. e.g. mass, length and time.

Question 4.
Why do we need multiples and sub-multiples of standard S.l. units.
Answer:
We need multiples and submultiples of standard S.I. units to maintain uniformity in measurements. To measure far of distances, we use multiple units. If we are to measure small lengths we use submultiples.

Question 5.
Give one example each where the following units are used :
(a) gram
(b) kilometre
(c) degree Celsius
(d) second
(e) hour
(f) hectare
Answer:
(a) gram – mass of body
(b) kilometre – distance
(c) degree Celsius – temperature
(d) second – time
(e) hour – time
(f) hectare – area

Question 6.
What do you understand by the S.I. system of measurement ?
Answer:
S.I. System of Measurement: The units that we use to measure fundamental quantities are called fundamental units. The S.I. system stands for syste’me Internationale d’Unites. It is a universal system of measurement. The S.I. system has seven basic units.

L. Which of the units would be best to measure the following distances ?

Question 1.
The distance from Mumbai to Pune
Answer:
The distance from Mumbai to Pune kilometre.

Question 2.
The length of a class-room
Answer:
The length of a class room metre

Question 3.
The length of your text-book
Answer:
The length of your text book centimetre

Question 4.
The thickness of an exercise-book
Answer:
The thickness of an exercise book millimetre.

Question 5.
What is the S.I. unit for measurement of length ?
Answer:
S.I. unit of length – metre

Question 6.
How are multiple and sub-multiple units releated to each other ?
Answer:
Multiple and sub-multiple units are related to each other by the power of 10
1 km = 10³ m
1 dm = 10^-1m
1 hm = 10² m
1 cm = 10^-2 m
1 dam = 10 m
1 mm = 10^-3 m

Question 7.
What unit will you use to measure the length of :
(a) a book ………… ?
(b) hockey field ………… ?
Answer:
(a) centimetre
(b) metre

Question 8.
Name the instrument to measure :
(a) length of a book
Answer:
length of a book : ruler.

(b) diameter of a round pencil
Answer:
diameter of a round pencil: Screw gauge.

(c) length of a football Held
Answer:
length of a football field : measuring tape.

Question 9.
Change the following masses from kilogram to gram:
(a) 5 kg
(b) 3.8 kg.
Answer:
(a) 5 kg = 5 x 1000 = 5000 gm
(b) 3.8 kg = 3.8 x 1000 = \(\frac {38}{10}\) x 1000 = 3800 gm

Question 10.
Change the following masses from gram to kilogram:
(a) 2600 g
(b) 800 g.
Answer:
(a) 2600g= \(\frac {2600}{1000}\) = 2.6 kg
(b) 800 g = \(\frac {800}{1000}\) = 0.8 kg

Question 11.
A measuring cylinder contains 20 cm of water. Four marbles of equal size are added to the measuring cylinder. The water level rises to 28 cm. What is the volume of :
(a) 4 marbles
(b) each marble ?
Answer:
(a) Initial volume of water = 20 cm
Final volume of water = 28 cm
Rise in water = 28 – 20 = 8 cm
Volume of 4 marbles = 8 cm

(b) Volume of each marble = \(\frac {8}{4}\) = 2 cm Ans.

M. Short Answer Questions :

Question 1.
Write true or false against each of the following statements :
(a) Area is the measure of surface of an object.
Answer:
False

(b) Cubit is the standard unit of measurement.
Answer:
False

(c) The S.I. unit of area is square metre.
Answer:
True

(d) The word capacity means the same as volume.
Answer:
True

(e) Mass is a measure of the quantity of matter.
Answer:
True

Question 2.
Fill in the blanks :

(a) The volume of an object is the ………….. occupied by it.
Answer:
The volume of an object is the space occupied by it.

(b) The S.I. unit of length is ………….
Answer:
The S.I. unit of length is metre.

(c) 1 cm³ is equal to …………. ml.
Answer:
1 cm³ is equal to 1 ml.

(d) The area of a rectangle is the product of its length and …………..
Answer:
The area of a rectangle is the product of its length and breadth.

(e) The volume of a liquid can be measured by using a
Answer:
The volume of a liquid can be measured by using a measuring cylinder.

(f) The cubic decimetre is better known as
Answer:
The cubic decimetre is better known as one litre.

Question 3.
(a) Answer the following in one word or one sentence.
(i) What is the standard unit of length ?
Answer:
metre

(ii) What is the S.I. unit of mass ?
Answer:
kilogram

(b) The S.I. unit of area is :
(i) m³
(ii) m⁵
(iii) m²
(iv) m⁴
Answer:
(iii) m²

(c) The S.I. unit of volume is
(i) m²
(ii) m³
(iii) m⁴
(iv) m⁵
Answer:
(ii) m³

(d) The S.I. unit of capacity is ………….
(i) cubic litre
(ii) centilitre
(iii) millilitre
(iv) Litre
Answer:
(iv) Litre

(e) The quantity of matter present in a body is called its
(i) mass
(ii) weight
(iii) pressure
(iv) force
Answer:
(i) mass

Question 4.
Match the following :

Column A	Column B
(a) Length of a field	(I) measuring jar
(b) Volume of a liquid	(II) measuring tape
(c) Mass	(iii) hectare
(d) Area	(iv) litre
(e) Cubic decimetre	(v) kilogram

Answer:

Column A	Column B
(a) Length of a field	(iii) hectare
(b) Volume of a liquid	(iv) litre
(c) Mass	(v) kilogram
(d) Area	(II) measuring tape
(e) Cubic decimetre	(I) measuring jar

Question 5.
Name the instrument which is used to measure the mass of a body.
Answer:
Mass of a body is measured by a beam balance.

Question 6.
What do you mean by volume ? What is its unit ?
Answer:
Volume : The space occupied by an object is known as its volume.
The unit of volume is m³ or litre.

Numericals

Question 7.
Ritu bought 6 packets of biscuits each containing SO biscuits. The weight of all packets was 2 kg and 500 gms. What is the weight of one biscuit ?
Answer:
No. of packets = 6
Each packet contains 50 biscuits
Total number of biscuits = 50 x 6 = 300
Total weight of biscuits = 2kg 500 gm
Wt. of each biscuit = \(\frac {2.500}{300}\) = 8.3 gm

Question 8.
One dozen of carom board coins were arranged one above the other. Their total height was 6 cm and 6 mm. What is the thickness of each coin ?
Answer:
Number of carom board coins = 12
Total height = 6 cm and 6 mm = 66 mm
Thickness of each coin = \(\frac {66}{12}\) = 5.5 mm Ans.

Question 9.
Calculate the mass of water in a tank of length 50 cm, breadth 40 cm and height 10 cm, if the mass of 1 cm3 of water is 1 gm.
Answer:
Length of tank (l) = 50 cm
Breadth of tank (b) = 40 cm
Height of tank = (h) = 10 cm
Mass (volume) of water = l x b x h
= 50 x 40 x 10 = 20000 gm
\(\frac {20000}{1000}\) = 20 kg Ans.

Question 10.
The length of a rectangular Held is 60 m and its width is 35 m. Calculate its area.
Answer:
Length of a rectangular field = 60 m Width = 35 m
Area = Length x Width = 60 x 35 = 2100 m² Ans.

Question 11.
How much water will fill a dish of size 10 cm x 10 cm x 5 cm ?
Answer:
Volume of water = Length x breadth x height
= 10 x 10 x 5 = 500 cm3 or 500 ml. Ans.

Question 12.
How will you measure the thickness of a one rupee coin ?
Answer:
Thickness of one rupee coin : Take fifteen coins together and stack closer to the ruler. Take the total thickness and then divide this thickness by 15 to get the thickness of one coin.
Let the thickness of stack = a cm
Number of coins =15
Thickness of one coin = a/15 cm

Question 13.
What are the uses of estimation and approximation ?
Answer:
a. Adding salt or sugar while cooking food.
b. Time to reach school.
c. A painter paints wall by mixing colour paint and oil by estimation only.

Question 14.
Why in case of infants, the thermometer is not put into their mouth while checking their fever ?
Answer:
the thermometer bulb contains mercury and bulb is liable to break and mercury is poisonous.

ICSE Class 6 Physics Important Questions