NEET UG 2002 — Thermodynamics

Consider two rods of the same length and different specific heats $\left(S_1, S_2\right)$, conductivities $\left(K_1, K_2\right)$ and area of cross sections $\left(A_1, A_2\right)$ and both having temperature $T_1$ and $T_2$ at their ends. If the rate of loss of heat due to conduction is equal then:

For a black body at temperature $727^{\circ} \mathrm{C}$, its radiating power is $60 \mathrm{~W}$ and the temperature of surrounding is $227^{\circ} \mathrm{C}$. If temperature of the black body is changed to $1227^{\circ} \mathrm{C}$, then its radiating power will be:

The efficiency of the Carnot engine is $50 \%$ and the temperature of the sink is $500 \mathrm{~K}$. If the temperature of the source is kept constant and its efficiency raised to $60 \%$, then the required temperature of the sink will be:

The Wien's displacement law expresses the relation between:

Unit of Stefan's constant is:

Which of the following is best close to an ideal black body?