List of top Physics Questions on thermal properties of matter asked in NEET (UG)

The energy that will be ideally radiated by a 100 kW transmitter in 1 hour is:
A cup of coffee cools from 90°C to 80°C in t minutes, when the room temperature is 20°C. The time taken by a similar cup of coffee to cool from 80°C to 60°C at a room temperature same at 20°C is
A copper rod of $88 \,cm$ and an aluminium rod of unknown length have their increase in length independent of increase in temperature. The length of aluminium rod is $(a_{C_{u}}=1.7 \times 10^{-5}\,K^{-1}$ and $\left.a_{A_{l}}=2.2 \times 10^{-5} K^{-1}\right)$
A spherical black body with a radius of $12\,cm$ radiates $450\,watt$ power at $500\,K$. If the radius were halved and the temperature doubled, the power radiated in watt would be :

Two rods \(A\) and \(B\) of different materials are welded together as shown in figure. Their thermal conductivities are \(K_1\) and \(K_2\). The thermal conductivity of the composite rod will be :

Coefficient of linear expansion of brass and steel rods are $\alpha_1$ and $\alpha_2$. Lengths of brass and steel rods are $ l_1$ and $l_2$ respectively. If $(l_2 - l_1)$ is maintained same at all temperatures, which one of the following relations holds good ?
A piece of ice falls from a height h so that it melts completely. Only one-quarter of the heat produced is absorbed by the ice and all energy of ice gets converted into heat during its fall. The value of h is : [Latent heat of ice is $3.4 \times 10^5 \, J/kg$ and $g = 10 \, N/kg$]
A body cools from a temperature $3T$ to $2T$ in $10\, minutes$. The room temperature is $T$. Assume that Newton�s law of cooling is applicable. The temperature of the body at the end of next $10\,minutes$ will be -
A black body is at a temperature of $5760 \,K$. The energy of radiation emitted by the body at wavelength $250\,nm$ is $U_1$, at wavelength $500\, nm$ is $U_2$ and that at $1000\,nm$ is $U_3$. Wien's constant, $b = 2.88 \times 10^6 \, nm\,K$. Which of the following is correct ?
Four rods with different radii $r$ and length $l$ are used to connect two heat reservoirs at different temperature. Which one will conduct most heat ?
Certain quantity of water cools from 70$^{\circ}$C to 60$^{\circ}$C in the first 5 minutes and to 54$^{\circ}$C in the next 5 minutes. The temperature of the surroundings is
Two metal rods $1$ and $2$ of same lengths have same temperature difference between their ends. Their thermal conductivities are $ K_1$ and $K_2 $ and cross sectional areas $ A_1 $ and $ A_ 2 $ respectively. If the rate of heat conduction in 1 is four times that in 2, then :
A piece of iron is heated in a flame. It first becomes dull red then becomes reddish yellow and finally turns to white hot. The correct explanation for the above observation is possible by using :
If the radius of a star is $R$ and it acts as a black body, what would be the temperature of the star, in which the rate of energy production is $ Q ? $ ($ \sigma $ stands for Stefan's constant)
A slab of stone of area 0.36 m2 and thickness 0.1 m is exposed on the lower surface to steam at 100$^{\circ}$C. A block of ice at 0$^{\circ}$C rests on the upper surface of the slab. In one hour 4.8 kg of ice is melted. The thermal conductivity of slab is (Given latent heat of fusion of ice = $ 3.36 \times 10^5 J kg^{-1})$
The total radiant energy per unit area, normal to the direction of incidence, received at a distance $R$ from the center of a star of radius $r$, whose outer surface radiates as a black body at a temperature $T K$ is given by (where $\sigma$ is Stefan's constant)
A cylindrical metallic rod in thermal contact with two reservoirs of heat at its two ends conducts an amount of heat $Q$ in time $t$. The metallic rod is melted and the material is formed into a rod of half the radius of the original rod. What is the amount of heat conducted by the new rod when placed in thermal contact with the two reservoirs in time $t$ ?
On a new scale of temperature (which is linear) and called the W scale, the freezing and boiling points of water are 39$^{\circ}$W and 239$^{\circ}$W respectively. What will be the temperature on the new scale, corresponding to a temperature of 39$^{\circ}$C on the Celsius scale?
Assuming the sun to have a spherical outer surface of radius r, radiating like a black body at temperature $t^{\circ} C$, the power received by a unit surface, (normal to the incident rays) at distance $R$ from the centre of the Sun is:- Where $\sigma$ is the Stefan's Constant.
A black body at 1227°C emits radiations with maximum intensity at a wavelength of 5000 Å. If the temperature of the body is increased by 1000°C, the maximum intensity will be observed at :
The temperature of inversion of a thermocouple is 620°C and the neutral temperature is 300°C.what is the temperature of cold junction?
Which of the following circular rods,(given radius r and length l)each made of the same material and whose ends are maintained at the same temperature will conduct most heat?
We consider the radiation emitted by the human body. Which of the following statements is true:

What is the cause of “Green house effect”

Consider two rods of the same length and different specific heats (S1, S2), conductivities (K1, K2), and area of cross-sections (A1, A2) and both having temperature T1 and T2 at their ends. If the rate of loss of heat due to conduction is equal, then