Which of the following has no effect on radiation?

Steel bars each of length 3m at 28°C are to be used for constructing a rail line. If the linear expansitivity of the steel is 1 x \(10^{-5}K^{-1}\),what is the safety gap that must be left between the successive bars if the highest temperature expected is 40°C?

Which of the following statements are correct? i. land and sea breezes are natural convection currents. ii. convection may occur in liquids or gasses but not in solids. iii. the vacuum in a thermos flask prevents heat loss due to convection only.

A hot metal ball is suspended in the open air. As it cools it loses heat by?

A water fall is 420m high. Calculate the difference in temperature of the water between the top and bottom of the water fall. Neglect heat loses(g = 10.0m-2 specific heat capacity of water = 4.20 x 10\(^3\) JKg-1 K-1)