Thermal Propert...

A solid sphere and a hollow sphere of the same material and size are heated to the same temperature and allowed t col in the same surroundings. If the temperature difference between each sphere and its surroundings is T, then

A solid copper cube of edges 1 cm is suspended in an evacuated enclosure. Its temperature is found to fall from 100^oC to 99^oC in 100 s. Another solid copper cube of edges 2 cm, with similar surface nature, is suspended in a similar manner. The time required for this cube to cool from 100^oC to 99^oC will be approximately

A body initially at 80^oC cools to 64^oC in 5 minutes and to 52^oC in 10 minutes. The temperature of the body after 15 minutes will be

A 5 cm thick ice block is there on the surface of water in a lake. The temperature of air is –10^oC; how much time it will take to double the thickness of the block?
(L = 80 cal/g, K_ice = 0.004 erg/s-k, d_ice = 0.92 g cm^–3)

A cylindrical rod with one end in a steam chamber and the other end in ice results in melting of 0.1 g of ice per second. If the rod is replaced by another with half the length and double the radius of the first and if the thermal conductivity of material of second rod is 1/4 that of first, the rate at which ice melts in g/s will be

one end of a copper rod of length 1.0 m and area of cross-section 10^–3 m² is immersed in boiling water and the other end in ice. If the coefficient of thermal conductivity of copper is 92 cal/m-s-^oC and the latent heat of ice is 8 × 10⁴ cal/kg, then the amount of ice which will melt in one minute is

An ice box used for keeping eatable cold bas a total wall area of 1 metre² and a wall thickness of 0.5 cm. The thermal conductivity of the ice box is K = 0.001 J/m-^oC. It is filled with ice at 0^oC along with eatables on a day when the temperature is 30^oC. The latent heat of fusion of ice is 334 × 10³ J/kg. The amount of ice melted in one day is (1 day = 86,400 seconds)

Five rods of same dimensions are arranged as shown in the figure. They have thermal conductivities K₁, K₂, K₃, K₄ and K₅. When points A and B are maintained at different temperatures, no heat flows through the central rod if

A hot metallic sphere of radius r radiates heat. It\'s rate of cooling is

A solid copper sphere (density ρ and specific heat capacity c) of radius r at an initial temperature 200 K is suspended inside a chamber whose walls are at almost 0 K. The time required (in μ s) for the temperature of the sphere to drop to 100 K is