Six identical rods are arranged as shown in the figure. The temperature of the junction $B$ will be......... $^oC$
$\frac{240}{3}$
$240$
$140$
$\frac{140}{3}$
The intensity of radiation emitted by the sun has its maximum value at a wavelength of $510\,nm$ and that emitted by the north star has the maximum value at $350\,nm$. If these stars behave like black bodies, then the ratio of thesurface temperature of the sun and north star is
A glass flask of volume $1$ litre is fully filled with mercury at $0\,^oC$. Both the flask and mercury are now heated to $100\,^oC$. If the coefficient of volume expansion of mercury is $1.82\times10^{-4}/^oC$, volume coefficient of linear expansion of glass is $10\times10^{-6}/^oC$, the amount of mercury which is spilted out is ............ $\mathrm{ml}$
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 $540\, cal/gm$)
A block of metal is heated to a temperature much higher than the room temperature and allowed to cool in a room free from air currents. Which of the following curves correctly represents the rate of cooling
In a composite rod, when two rods of different lengths $l_1$ and $l_2$ and of the same cross-sectional area are joined from end to end then if $K$ is the effective coefficient of thermal conductivity, the value of $(l_1 + l_2)/K$ is