Frank ICSE Solutions for Class 10 Physics Chapter 5-Heat, Heat Calorimetry, Heat Change Of State

Frank ICSE Solutions for Class 10 Physics Chapter 5-Heat, Heat Calorimetry, Heat Change Of State

Solution 1
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(a)J/kg ^oC(b)2000 / (4 x 3) J/kg ^oC(c)AB and CD(d)Latent heat is emitted(e)The first time when temperature is constant represents change of state from solid to liquid and the second time temperature is constant represents change of state from liquid to vapour.
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Solution 2
(a)Heat capacity of a body is the quantity of heat required to raise its temperature by 1^oC. It depends upon the mass and the nature of the body.Units: J/^oC or calorie/^oC(b)Change in temperature = (50-30) = 20^oC Amount of heat required, Q = m x C x ?T = 0.5 x 4200 x 20 = 42000 J
Solution 3
(a)This means that 390 J of heat is required to raise the temperature of 1kg of copper by 1^oC.(b)Change in temperature = (100-30) = 70^oC = 70 KAmount of heat given out, Q = m x C x T = 0.6 x 900 x 70 = 37800 J
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Solution 18
(a) Ice melts under pressure. So, when the steel blades of the skates pressed on the ice, the ice melts. The water formed makes the skates slide easily over the ice, reducing friction. So, when we are skating on ice, we are skating on a thin film of water, which acts like lubricating oil. Nothing such happens in case of glass.
(b) Sand improves the friction between car tyres and the road, so cars don’t skid on icy surfaces. Salt is spread so as to decrease the melting point of ice. Ice on the roads melt, making the roads less slippery.
(c) Steam burn is worse than a hot water burn because 1 g of steam gives out 540 calories of additional heat.
(d) Lumps of ice cool better than cold water because each gram of ice requires additional 80 calories of heat to get converted into water. Hence, cooling capacity of lumps of ice is more than cold water.
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Solution 32
Steam at 100^oC will produce more severe burns because every gram of steam gives out 2260 J of heat energy while condensing. This much amount of heat is additional to the heat contained in one gram of boiling water.
Solution 33
Ice cream appears colder to mouth than water at 0⁰C because it can extract approximately 80 cal/g (latent heat of fusion of ice)more heat from as compared to water at 0 ⁰C.
Solution 34
Although both ice cubes and iced water are at 0oC but ice cubes cool more quickly because each gram of ice requires additional 80 calories of heat to get converted into water at the same temperature, i.e., at 0^oC. Hence, the cooling capacity of ice cubes is more than that of iced water.
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Solution 37
1 gram of ice at 0^oC requires 80 calories of heat to get converted into 1 gram of water at 0^oC. So, water has more heat.
Solution 38
1 gram of water at 100^oC requires 540 calories of heat to get converted into 1 gram of steam at 100^oC. So, steam has more heat.
Solution 39
1 gram of ice at 0^oC requires additional 80 calories of heat to get converted into water at 0^oC. Then, heat is provided to raise the temperature to 10^oC. Therefore, ice requires more heat than water and the additional heat is known as ‘Latent heat of fusion of ice’.
Solution 40
Pressure cooker increases the pressure and hence the boiling point increases. So, the boiling point becomes greater than 373kelvin