Thermal properties of matter practice · Mixed difficulty

Mechanism of heat-transfer involved in freezing of lakes in colder region -

Assertion (A): When a strip made of iron and copper is heated it bends with iron on concave side.
Reason (R): Coefficient of linear expansion of copper is more than that of iron.

Assertion (A): Clothes dry faster when wind is blowing.
Reason (R): At the boiling point, the saturation vapour pressure equals the external pressure.

Statement-I: An iron ball strucked in a brass plate is removed by heating the system.
Statement-II: The coefficient of linear expansion of brass is more than that of iron.

The layers of atomsphere are heated through

(A): Specific heat of a body is always greater than its thermal capacity
(R): Thermal capacity is the heat required for raising temperature of unit mass of the body through unit degree.

Iron ball of mass $0.15 \mathrm{~kg}$ and specific heat capacity of $0.45 \mathrm{~J} / \mathrm{g}^{\circ} \mathrm{C}$ have same water equivalent of unknown material having mass 20 grams. Find specific heat capacity of this unknown material.

Consider the following two statements
(a) Celsius is the smallest unit of temperature
(b) The absorbance of a perfect black body is unity
The correct statement(s) is/are

(A): The melting point of ice decreases with increase of pressure.
(R): Ice contracts on melting.

Temperature of water at the surface of lake is $- {20^0}C$. Then temperature of water just below the lower surface of ice layer is

A hot and a cold body are kept in vacuum separated from each other. Which of the following cause decrease in temperature of the hot body

Which of the following statements is wrong?

It is seen that in proper ventilation of building, windows must be opened near the bottom and the top of the walls, so as to let pass

When a copper solid sphere is heated, its
(a) Moment of inertia increases
(b) Elasticity decreases
(c) Density decreases
(d) Mass increases

Assertion: Pressure in a real gas is less than that in an ideal gas
Reason: Force of attraction is non-zero in a real gas.

Temperature of the star is determined by

Density $\rho$, mass $m$ and volume $V$ are related as $\rho=m / V$. then $\gamma=$

An ice box made of Styrofoam (Thermal conductivity=0.01 $J{m^{ - 1}}{s^{ - 1}}{K^{ - 1}}$) is used to keep liquids cool. It has a total wall area including lid of 0.8 ${m^2}$ and wall thickness of 0.2 cm. A bottle of water is placed in the box and filled with ice. If the outside temperature is ${30^0}$ the rate flow of heat into the box is (in $J{s^{ - 1}}$ )

Absorptive power of a black body is

Two cylindrical conductors $A\;\mathrm{and}\;B$ of same metallic material have their diameters in the ratio $1\;:2$ and lengths in the ratio $2\;:1$. If the temperature difference between their ends is same, the ratio of heat conducted respectively by $A\;\mathrm{and}\;B$ per second is

The density of a liquid of coefficient of cubical expansion $r$ is $p$ at ${0^0}C$ when the liquid is heated to a temperature $T$ , the change in density will be

The value of coefficient of volume expansion of glycerin is $5 \times {10^{ - 4}}{\mathrm{K}^{ - 1}}$. The fractional change in the density of glycerin for a rise of $\mathrm{40^\circ C}$ in its temperature is:

Identify the meaningless

A test tube containing water is placed in boiling water so that its mouth remains outside the boiling water. Choose the wrong statement.

The amount of radiation emitted by a perfectly black body is proportional to

Assertion (A): In summer, the pendulum clock runs slow.
Reason (R): As temperature increases, length of the pendulum decreases and time period decreases.

Which of the following statements is true/correct

Statement 1: When a solid melts of a liquid boils, the temperature does not increase when heat is supplied.
Statement 2: The heat supplied is used to increase internal kinetic energy.

A metal piece is heated upto ${T^0}$ abs. The temperature of the surrounding is ${t^0}$ abs. The heat in the surrounding due to radiation is proportional to

Assertion: A fluid in vacuum expands such that it changes to gaseous state. Its temperature decreases.
Reason: It uses its internal energy as heat of vaporization.