List of top Physics Questions on Heat Transfer

In given circuit, reading of voltmeter is 1 V, then resistance of

Ice at temperature –10°C is converted to steam at 100°C, the curve plotted between temperature (T) and time (t) when it is being heated by constant power source is

The specific heat capacity of a substance is temperature dependent and is given by the formula C = kT, where k is a constant of suitable dimensions in SI units, and T is the absolute temperature. If the heat required to raise the temperature of 1 kg of the substance from −73 ° C to 27 ° C is nk, the value of n is ___[Given: 0 K = −273 °C.]

Two plates A and B have thermal conductivities 84 \(Wm^{-1}K^{-1}\) and 126 \(Wm^{-1}K^{-1}\) respectively. They have same surface area and same thickness. They are placed in contact along their surfaces. If the temperatures of the outer surfaces of A and B are kept at 100 °C and 0 ºC respectively, then the temperature of the surface of contact in steady state is ________°C.

Given below are two statements: one is labelled as Assertion A and the other is labelled as Reason R.
Assertion A: Alloys such as constantan and manganin are used in making standard resistance coils.
Reason R: Constantan and manganin have very small value of temperature coefficient of resistance.
In the light of the above statements, choose the correct answer from the options given below.

300 cal. of heat is given to a heat engine and it rejects 225 cal. of heat. If source temperature is 227°C, then the temperature of sink will be _______°C.

A diatomic gas\( (γ = 1.4)\) does \(400\) \(J\) of work when it is expanded isobarically. The heat given to the gas in the process is ________ \(J\).

One mole of an ideal monoatomic gas is taken through the cycle ABCD as shown in the figure. If initial pressure, volume and temperature at point A are P_i, V_i, and T respectively, then choose the correct option (s).

A container with $1 \,kg$ of water in it is kept in sunlight, which causes the water to get warmer than the surroundings. The average energy per unit time per unit area received due to the sunlight is $700\, Wm ^{-2}$ and it is absorbed by the water over an effective area of $0.05\, m ^{2}$ .Assuming that the heat loss from the water to the surroundings is governed by Newton's law of cooling, the difference (in ${ }^{\circ} C$ ) in the temperature of water and the surroundings after a long time will be _______ .(Ignore effect of the container, and take constant for Newton's law of cooling $=0.001\, s ^{-1}$, Heat capacity of water $=4200\, J \,kg ^{-1} K ^{-1}$ )

A certain amount of heat energy is supplied to a monoatomic ideal gas which expands at constant pressure. What fraction of the heat energy is converted into work ?

A sphere, a cube and a thin circular plate all of same material and same mass initially heated to same high temperature are allowed to cool down under similar conditions. Then the

A deep rectangular pond of surface are A, containing water (density = r, specific heat capacity = s), is located in a region where the outside air temperature is at a steady value of -26°C. The thickness of the frozen ice layer in this pond, at a certain instant is x. Taking the thermal conductivity of ice as K, and its specific latent heat of fusion as L, the rate of increase of the thickness of ice layer, at this instant would be given by :-

A carnot engine takes 300 calories of heat at 500 K and rejects 150 calories of heat to the sink. The temperature of the sink is

Temperature difference of \(120^{\circ}C\) is maintained between two ends of a uniform rod \(AB\) of length \(2L\). Another bent rod \(PQ\), of same cross section as \(AB\) and length \(\frac{3L}{2}\) , is connected across \(AB\) (See figure). In steady state, temperature difference between \(P\) and \(Q\) will be close to :

One rod of length 2 m and thermal conductivity 50 unit is attached to another rod of length 1 m and thermal conductivity 100 unit. Temperature of free ends are 70°C and 50°C respectively. Then temperature of junction point will be

If the heat of $ 110\,\,J $ is added to a gaseous system, whose internal energy is $ 40\,\,J $ , then the amount of external work done is:

The $SI$ unit and dimensions of Stefan?s constant $\sigma$ in case of Stefan?s law of radiation is

Two bodies $A$ and $B$ are placed in an evacuated vessel maintained at a temperature of $27^{\circ} C$. The temperature of $A$ is $327^{\circ} C$ and that of $B$ is $227^{\circ} C$. The ratio of heat loss from $A$ and $B$ is about

The diagrams below show regions of equipotentials.

A positive charge is moved from A to B in each diagram.

Two spherical black bodies have radii $?r_1?$ and $'r_2'$ . Their surface temperatures are $'T_1'$ and $'T_2'$. If they radiate same power then $\frac{r_2}{r_1}$ is

The dimensions of Stefan?? constant are

The two ends of a metal rod are maintained at temperatures 100$^{\circ}$C and 110$^{\circ}$C. The rate of heat flow in the rod is found to be 4.0 J/s. If the end are maintained at temperatures 200$^{\circ}$C and 210$^{\circ}$C, the rate of heat flow will be

A uniform metallic rod rotates about its perpendicular bisector with constant angular speed. If it is heated uniformly to raise its temperature slightly, then