A temperature of \(100^{\circ}\text {F}\) (Fahrenheit scale) is equal to \(T~\text{K}\) (Kelvin scale). The value of \(T\) is:
1. \(310.9\)
2. \(37.8\)
3. \(100\)
4. \(122.4\)

A body cools down from \(80^{\circ}\mathrm{C}\) $\mathrm{to}$ \(70^{\circ}\mathrm{C}\) in 5 minutes. The temperature of the same body will fall from \(70^{\circ}\mathrm{C}\)$\mathrm{}$ $\mathrm{to}$ \(60^{\circ}\mathrm{C}\)$\mathrm{}$ in:

If \(\lambda_m\) is the wavelength, corresponding to which the radiant intensity of a block is at its maximum and its absolute temperature is \(T,\) then which of the following graphs correctly represents the variation of \(T?\)

1.		2.
3.		4.

A pendulum clock runs faster by \(5\) s per day at \(20^{\circ}\mathrm {C}\) and goes slow by \(10\) s per day at \(35^{\circ}\mathrm {C}\). It shows the correct time at a temperature of:
1. \(27.5^{\circ}\mathrm {C}\)
2. \(25^{\circ}\mathrm {C}\)
3. \(30^{\circ}\mathrm {C}\)
4. \(33^{\circ}\mathrm {C}\)

A constrained steel rod of length \(l\), area of cross-section \(A\), Young's modulus \(Y\) and coefficient of linear expansion \(\alpha\)$$ is heated through \(t^{\circ}\text{C}\)$$. The work that can be performed by the rod when heated is:
1. \((YA\alpha t)(l\alpha t)\)
2. \(\frac{1}{2}(YA\alpha t)(l\alpha t)\)
3. \(\frac{1}{2}(YA\alpha t)\frac{1}{2}(l\alpha t)\)
4. \(2(YA\alpha t)(l\alpha t)\)

Two rods, A and B, of different materials having the same cross-sectional area are welded together as shown in the figure. Their thermal conductivities are $K_1$ and $K_2$. The thermal conductivity of the composite rod will be:

1. $\frac{K_1+K_2}{2}$
2. $\frac{3\left(K_1+K_2\right)}{2}$
3. $K_1+K_2$
4. $2\left(K_1+K_2\right)$

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 watts would be:
1. \(225\)
2. \(450\)
3. \(1000\)
4. \(1800\)

The coefficients 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 the same at all temperatures, Which one of the following relations holds good?
1. \(\alpha_1 l_2^2=\alpha_2l_1^2\)
2. \(\alpha_1^2 l_2=\alpha_2^2l_1\)
3. \(\alpha_1 l_1=\alpha_2l_2\)
4. \(\alpha_1 l_2=\alpha_2l_1\)

A black body is at a temperature of 5760 K. The energy of radiation emitted by the body at a wavelength of 250 nm is U₁, at a wavelength of 500 nm is U₂ and that at 1000 nm is U₃. Given Wien's constant $b=2.88\times {10}^6$ $nm-\mathrm{K,\; which }$of the following is correct?
1. U₃=0       
2. U₁>U₂
3. U₂>U₁     
4. U₁=0

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 \(3.4\times10^5\) J/kg and \(g=10\) N/kg)