Previous Year Physics Question Papers (with solutions) of Kerala State Syllabus of Higher Secondary Examinations. Chapter Name: THERMAL PROPERTIES OF MATTER

a) Which among the following possess the highest specific heat capacity?
i. Water ii. Silver iii. Copper iv. Steel
b) You are in restaurant waiting for your friend and ordered coffee. It has arrived. Do you add sugar in your friend’s coffee and then wait for him or do you add sugar after the arrives? Explain with respect to the concept of cooling.
c) Read the statement given in a book “All thermal conductors are electrical conductors also.” Do you agree with this statement? If your answer is No, clarify it.

a) i. Water
b) Add sugar first, this will decrease the temperature of the coffee. Then the rate of cooling decreases (Newton"s law of cooling).
c) No, For example, Mica is a good conductor of heat but it is an insulator.

Temperature is the degree of hotness of the body.
a) Temperature of a normal human body is 98.6⁰ F. What is the corresponding temperature shown in the Celsius scale?
b) Specific heat capacity of water is 4186J/kg/K. What do you understand by the term, specific heat?
c) A brass tumbler feels much colder than a wooden tray on a chilly day. Why?
d) A brass boiler has a base area of 0.15m² and thickness 1.0 cm. It boils water at the rate of 6.0 kg/minute when placed on a gas stove. Estimate the temperature of the part of the flame in contact with the boiler. Thermal conductivity of brass = 109 Js ^-1 m^-1 K^-1. Heat of vaporization of water = 2256 x 10³ J kg^-1.

a) 37^oC
b) Specific heat capacity of a substance is the amount of heat required to increase the temperatue of unit mass of a substance by one unit
c) Thermal conductivity of brass tumbler is much larger than that of wooden tray.
d) See figure

There are three distinct modes of heat transfer.
a) The main mode of transmission of heat by which the sun heats the surface of the earth is:
i) Conduction ii) Radiation iii) Convection iv) None of these
b) Explain briefly, the occurrence of a sea breeze based on heat transfer.

a) ii) Radiation
b) Convection causes land and sea breezes to occur.
During day time, Earth surface heats up more quickly than Water surface. It creates breeze from Sea to Earth
At night, Earth surface cools down more quickly than Water surface, It create breeze from Earth to Sea

Complete the table.

Temperature	Kelvin scale	Celsius scale	Fahrenheit scale
Steam point	373.15 K	……………..	212.00 ⁰ F
Ice point	………………..	0.00 ⁰ C	………………..
Absolute zero	0.00 K	………………..	459.69 ⁰ F

Temperature	Kelvin scale	Celsius scale	Fahrenheit scale
Steam point	373.15 K	100 ⁰C	212.00 ⁰ F
Ice point	273.15 K	0.00 ⁰C	32 ⁰F
Absolute zero	0.00 K	- 273.15 ⁰C	459.69 ⁰ F

A steel beam of length 5m is kept at a temperature of 20⁰ C. On a hot day, the temperature rises to 40⁰ C. What is the change in its length due to thermal expansion?
(Coefficient to linear expansion of steel is 1.2 x 10^-5 / ⁰C)

A hole is drilled in a copper sheet. The diameter of the hole is 4.24 cm at 27⁰C. What is the change in diameter of the hole when the is heated to 227 ⁰C? (Coefficient of linear expansion of copper = 1.7 x 10 ^-5 / ⁰C).

When 0.15 kg of ice at 0°C is mixed with 0.30 kg of water at 50°C. in a container, the resulting temperature is 6.7°C. Calculate the latent heat of fusion of ice. Given specific heat capacity of water 4186 J kg^-1K^-1

Heat gained by ice = heat lost by the water
Or
Heat absorbed for phase change + Heat absorbed to increase Temperture = Heat lost by the water
m_iceL + m_iceC ΔT_ice = m_waterC ΔT_water
m_ice = 0.15 kg
m_water = 0.30 kg
ΔT_ice = 6.7°C
ΔT_water = 50 - 6.7 = 43.3°C
C = 4186 J kg^-1K^-1
Substitute above values, we get L = 334461.40 Joules/Kg

It is the change of state from Solid state to Vapour state without passing through Liguid state
Example: Dry ice or solid carbon dioxide sublimes.

Temperature is the degree of hotness of a body.
(a) Temperature of a normal human body is 98.6 °F. What is the corresponding temperature in the Celsius scale ?
(b) Define latent heat.
(c) Why a brass tumbler feels much colder than a wooden tray on a chilly day ?

a) (98.6°F − 32) × 5/9 = 37°C
b) It is the heat required to convert a solid into a liquid or vapour, or a liquid into a vapour, without change of temperature.
c) Brass is a good conductor of heat than wood