The graph shown in the adjacent diagram, represents the variation of temperature (T) of two bodies X and Y having the same surface area, with time (t) due to the emission of radiation. Find the correct relation between the emissivity and absorptivity power of the two bodies ?

      

A wall has two layers A and B each made of a different material. Both layers have the same thickness, the thermal conductivity of the material of A is twice that of B. Under thermal equilibrium, the temperature difference across the wall is 36^oC. The temperature difference across the layer A will be:

The earth receives at its surface radiation from the sun at the rate of  1,400 Wm^-2. The distance of the centre of the sun from the surface of the earthy is 1.5 x 10¹¹ m and the radius of the sun is 70 x 10⁸ m. Treating sun as a black body, it follows from the above data that its surface temperature is:

A pressure cooker reduces cooking time for food, why ?

Compared to burn due to air at 100^oC, a burn due to steam at 100^oC is :

Let 50 g of ice at 0^oC is mixed with 50 g of water at 80^oC, final temperature of mixture of will be:

Heat capacity of a body is infinite.  It means

A black body radiates heat energy at the rate of 2 × 10⁵ J/s/m² at a temperature of 127°C. The temperature of black body at which the rate of radiation is 32 × 10⁵ J/s/m² is

During constant temperature, we feel colder on the day when the relative humidity is

Which of the following is  closer to a black body ?