Thermal properties of matter practice · Medium

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.

(A): Water is used as a coolant in automobile radiators as well as a heater in hot water bags.
(R): Water has high specific heat capacity.

Statement-1: At a steelworks, molten iron is heated to $1500^{\circ} \mathrm{C}$ to remove impurities. It is accurate to say that molten iron contains more heat than solid iron.
Statement-2: Solid iron at melting point needs to be supplied heat corresponding to its latent heat of fusion for phase change.

A solid sphere and a hollow sphere are heated the same temperature. Point out the true statement.

No other thermometer is as suitable as a platinum resistance thermometer to measure temperature in the entire range of

Assertion (A) : Heat is supplied at constant rate from one end of a conducting rod. In steady state, temperature of all points of the rod becomes uniform.

Reason (R) : In steady state, temperature of rod does not increase.

Assertion: According to Newton's law of cooling, the rate of loss of heat, $-\frac{d Q}{d t}$ of the body is directly proportional to the difference of temperature.
Reason: This law holds for all type of temperature differences.

Statement -I: The linear expansion does not depend on nature of the material, initial length, and rise in temperature.
Statement-II: The coefficient of linear expansion depends on nature of the material and system of temperature.

Absorption co-efficient of an open window is

A graph is plotted with $PV/T$ on ${y}$-axis and mass of the along ${X}$-axis for different gases. The graph is

According to Wien's law

Two liquids ${A}$ and ${B}$ are at $32^{\circ} \mathrm{C}$ and $24^{\circ} \mathrm{C}$. When mixed in equal masses, the temperature of mixture is found to be $28{ }^{\circ} \mathrm{C}$. Their specific heats are in the ratio

Two rods A and B are of equal lengths. Their ends are kept between the same temperature and their area of cross-sections are ${A_1}$ and ${A_2}$ and thermal conductivities ${K_1}$ and ${K_2}$. The rate of heat transmission in the two rods will be equal, if

A black body has maximum wavelength $\lambda m$ at temperature 2000 K. Its corresponding wavelength at temperature 3000 K will be

Assertion (A): A brass disc fits snugly in the hole of the iron plate. To remove the disc the combination must be heated.
Reason (R): The coefficient of linear expansion of brass is less than that of iron

There are two identical vessels filled with equal amounts of ice. The vessels are of different metals., If the ice melts in the two vessels in 20 and 35 minutes respectively, the ratio of the coefficients of thermal conductivity of the two metals is

A flask of volume ${10^3}$ cc is completely filled with mercury at 0$^ \circ C$. The coefficient of cubical expansion of mercury is 180 $\times {10^{ - 6}}^ \circ {C^{ - 1}}$ and that of glass is $40 \times {10^{ - 6}}^ \circ {C^{ - 1}}$.
If the flask in now placed in boiling water at 100$^ \circ C$, how much mercury will overflow?

$1 \,{gm}$ of ice at $0^{\circ}\, {C}$ is mixed with $2\, {gm}$ of water at $90^{\circ}\, {C}$. The final temperature of the mixture will be

When the pressure on water is increased the boiling temperature of water as compared to ${100^0}C$ will be

Three bars of equal lengths and equal area of cross-section are connected in series. Their thermal conductivities are in the ratio of $2: 4: 3$. If the open ends of the first and the last bars are at temperatures $200^{\circ} \mathrm{C}$ and $18^{\circ} \mathrm{C}$ respectively in the steady state, calculate the temperatures of both the junctions.

Which of the following statement(s) is/are correct?

I. Gravity plays very important role in the process of natural convection.

II. Convection mainly takes place in liquids and gases.

A cylinder of radius $\mathrm{R}$ made of a material of thermal conductivity $\mathrm{K}_1$ is surrounded by a cylindrical shell of inner radius $\mathrm{R}$ and outer radius $2 \mathrm{R}$ made of a material of thermal conductivity $\mathrm{K}_2$. The two ends of the combined system are maintained at two different temperatures. There is no loss of heat across the cylindrical surface and the system is in steady state. The effective thermal conductivity of the system is -

Consider the following statements.

(A) Convection involves flow of matter within a fluid due to unequal temperatures of its parts.

(B) The change of solid state to vapour state without passing through liquid state is called sublimation.

Based on above information, pick correct option.

Statement-I: To have same difference between the lengths of two metallic rods their initial lengths of $0^{\circ} \mathrm{C}$ should be in the inverse ratio of their coefficient of linear expansion.
Statement-II: If the lengths of two metallic rods at $0^{\circ} \mathrm{C}$ are in the inverse ratio of their coefficient of linear expansion then the change in the lengths due to same rise of temperature is same.

During melting process, the heat given to a body is utilised in

At what temperature is the Fahrenheit scale reading equal to twice of Celsius scale reading?

A solid ball of metal has a concentric spherical cavity within it. If the ball is heated, the volume of the cavity will

Star A has radius r surface temperature T while Star B has radius 4r and surface temperature T/2. The ratio of the power of two starts ${P_A}:{P_B}$ is