Six identical rods are arranged as shown in the figure. The temperature of the junction $B$ will be......... $^oC$
$\frac{240}{3}$
$240$
$140$
$\frac{140}{3}$
Two electric lamps $A$ and $B$ radiate the same power. Their filaments have the same dimensions and have emissivities $e_A$ and $e_B$. Their surface temperatures are $T_A$ and $T_B$. The ratio $\frac{{{T_A}}}{{{T_B}}}$ will be equal to :-
Gravitational force is required for
The temperature of a black body reduces to half of its actual value. By what fraction will the amount of radiations given out reduce?
Two bodies $P$ and $Q$ have thermal emissivities of $\varepsilon_P$ and $\varepsilon_Q$ respectively. Surface areas of these bodies are same and the total radiant power is also emitted at the same rate. If temperature of $P$ is $\theta_P$ kelvin then temperature of $Q$ i.e. $\theta_Q$ is
Steam is passed into $22\, g$ of water at $20\,^oC$ . The mass of water that will be present when the water acquires a temperature of $90\,^oC$ is ............ $\mathrm{gm}$ (Latent heat of steam is $540\, cal/gm$)