{"id":29375,"date":"2023-03-13T07:33:45","date_gmt":"2023-03-13T02:03:45","guid":{"rendered":"https:\/\/icsesolutions.com\/?p=29375"},"modified":"2023-03-14T09:53:52","modified_gmt":"2023-03-14T04:23:52","slug":"a-new-approach-to-icse-physics-part-1-class-9-solutions-heat-and-energy","status":"publish","type":"post","link":"https:\/\/icsesolutions.com\/a-new-approach-to-icse-physics-part-1-class-9-solutions-heat-and-energy\/","title":{"rendered":"A New Approach to ICSE Physics Part 1 Class 9 Solutions Heat and Energy"},"content":{"rendered":"
These Solutions are part of A New Approach to ICSE Physics Part 1 Class 9 Solutions<\/a>. Here we have given A New Approach to ICSE Physics Part 1 Class 9 Solutions Heat and Energy.<\/p>\n Exercise<\/strong><\/span><\/p>\n Question 1.<\/strong><\/span> (a) Heat energy :<\/strong> It is a form of energy which causes in us the sensation of hotness or coldness. Question 2.<\/strong><\/span> (a) Temperature :<\/strong> The degree of hotness coldness of a body is called temperature. OR<\/strong> Temperature is the effect of heat energy which determines the thermal state of a body. Question 3.<\/strong><\/span> Temperature :<\/strong><\/p>\n Question 4.<\/strong><\/span> Question 5.<\/strong><\/span> Question 6.<\/strong><\/span> Question 7.<\/strong><\/span> Question 8.<\/strong><\/span> <\/p>\n Mass 5 cm3<\/sup> of water is 5 g Question 9.<\/strong><\/span> Question 10.<\/strong><\/span> Question 11.<\/strong><\/span> Question 12.<\/strong><\/span> Question 13.<\/strong><\/span> Question 14.<\/strong><\/span> Question 15.<\/strong><\/span> Question 16.<\/strong><\/span> Question 17.<\/strong><\/span> Answer:<\/strong><\/span><\/p>\n Question 18.<\/strong><\/span> Question 19.<\/strong><\/span> Question 20.<\/strong><\/span> Question 21.<\/strong><\/span> More Resources<\/strong><\/p>\n
\nDefine heat energy (a)<\/strong> on conventional basis (b)<\/strong> on the basis of kinetic theory of matter.
\nAnswer:<\/strong><\/span><\/p>\n
\n(b) Heat energy :<\/strong> On the basis of kinetic theory of matter, heat energy is defined as the sum total of kinetic and potential energies of all the molecules of a given substance.<\/p>\n
\nDefine temperature (a)<\/strong> on conventional basis (b)<\/strong> on the basis of kinetic theory of matter.
\nAnswer:<\/strong><\/span><\/p>\n
\n(b) Temperature :<\/strong> On the basis of kinetic theory of matter, temperature is the average kinetic energy of all the molecules of a substance.<\/p>\n
\nState three differences between heat and temperature.
\nAnswer:<\/strong><\/span>
\nHeat :<\/strong><\/p>\n\n
\n
\nDefine calorie. How many joules make one calorie?
\nAnswer:<\/strong><\/span>
\nOne Calorie :<\/strong> One calorie is the amount of heat energy required to raise the temperature of one gram of water through 1\u00b0C.
\nThere are 4.2 J in one calorie
\n1 Cal = 4.2 J<\/p>\n
\nA body absorbs 1680 J of heat energy. How many calories of heat is absorbed by the body?
\nAnswer:<\/strong><\/span>
\nHeat energy absorbed by body = Q = 1680 J
\nWe know 1 cal = 4.2 J
\n\u2192 Q = 1680 J = 1680\/4.2 Cal
\nQ = 400 Cal<\/p>\n
\nA body radiates out 300 calories of heat energy. How much heat energy is radiated out by the body in joules?
\nAnswer:<\/strong><\/span>
\nHeat energy radiated by the body = Q = 300 Cal
\nAs 1 cal = 4.2 J
\nQ = 300 Cal = 300 \u00d7 4.2 J
\nQ = 1260 J<\/p>\n
\nWhat do you understand by the anomalous expansion of water?
\nAnswer:<\/strong><\/span>
\nAnomalous expansion : A liquid which does not behave like a normal liquid on heating or cooling is said to have anomalous expansion. On heating or cooling, water does not behave like a normal liquid. Volume of water increases if we heat or cool it, provided initially the water is at 4\u00b0C.<\/p>\n
\nDraw a graph between volume and temperature, when 5 cm3<\/sup> of ice at -10\u00b0C is heated to form water at +10\u00b0C.
\nAnswer:<\/strong><\/span><\/p>\n
\nVolume of water in minimum at 4\u00b0C.<\/p>\n
\nHow do fishes survive in frozen lakes?
\nAnswer:<\/strong><\/span>
\nFishes survive in pond even when the atmospheric temperature is below 0\u00b0C. It is because of anomalous expansion of water. When the temperature falls below 0\u00b0C water changes into ice and rises to the top and ice being poor conductor of heat helps to keep water below it at 4\u00b0C and fish can live in pond water.<\/p>\n
\nExplain, why are soft drink bottles not completely filled?
\nAnswer:<\/strong><\/span>
\nOn lowering the temperature below 4\u00b0C, water expands due to its anomalous behaviour. So, if soft drink bottles are completely filled, then they may burst and cause accident. As a result, soft drink bottles are not completely filled.<\/p>\n
\nExplain, why do water pipes burst during severe winter?
\nAnswer:<\/strong><\/span>
\nIn severe winter, water pipe lines often burst because water freeze at sub-zero temperature and in doing so expands. Since there is no space within the pipes for expanding ice, it exerts very large pressure and bursts open the steel pipes.<\/p>\n
\nExplain, why does a glass bottle completely filled with water and tightly capped burst when placed in a freezer?
\nAnswer:<\/strong><\/span>
\nA glass bottle completely filled with water and closed tightly is likely to burst in the freezer of refrigerator because water changes into ice and its volume increases. Since water when cooled from 4\u00b0C to 0\u00b0C expands. Thus, exerts large pressure and glass bottle bursts.<\/p>\n
\nExplain, why are the taps left dripping in sub-zero temperature during winter?
\nAnswer:<\/strong><\/span>
\nWater freezes at sub-zero temperature and in doing so expands (anomalous behaviour of water).
\nSo taps are left dripping in sub-zero temperature during winter so as to provide sufficient space for expansion of freezing water.<\/p>\n
\nExplain, why are the exposed water pipes lagged with straw during severe winter?
\nAnswer:<\/strong><\/span>
\nWater freezes at sub-zero temperature and in doing so expands (anomalous behaviour of water). So exposed water pipes during severe winter are lagged with straw so as to provide sufficient space for expansion of freezing water.<\/p>\n
\nExplain why do vegetables and fruits get damaged during severe frost?
\nAnswer:<\/strong><\/span>
\nVegetables and fruits get damaged during severe fruits because the water present in them on freezing expands and burst open the cell walls of cells.<\/p>\n
\nAt what temperature the pure water has (a)<\/strong> maximum density (b)<\/strong> minimum volume?
\nAnswer:<\/strong><\/span>
\nAt 4\u00b0C, pure water has maximum density and minimum volume.<\/p>\n
\nA deep pond of water has its top layer frozen. What will be the likely temperature of water layer<\/p>\n\n
\n
\nWhat is greenhouse effect?
\nAnswer:<\/strong><\/span>
\nThe process by which absorption and emission of infra-red radiation by the atmospheric gases warm up the surface of a planet and its lower atmosphere is called green-house effect.<\/p>\n
\nWhich gas is chiefly responsible for global warming?
\nAnswer:<\/strong><\/span>
\nCarbon dioxide gas is chiefly responsible for global warming.<\/p>\n
\nHow can global warming can be reduced?
\nAnswer:<\/strong><\/span>
\nWith increasing economic growth and population, energy consumption is increasing and hence this leads to global warming. To minimise global warming following three measures should be taken.<\/p>\n\n
\nState four effects of global warming.
\nAnswer:<\/strong><\/span>
\nThe effects of global warming on the life on earth is as below :<\/strong><\/p>\n\n
\n