Two spheres of the same material have radii $$1$$ $$m$$ and $$4$$ $$m$$ and temperatures $$4000$$ $$K$$ and $$2000$$ $$K$$ respectively. The ratio of the energy radiated per second by the first sphere to that by the second is

At what temperature is the $$r.m.s$$ velocity of a hydrogen molecule equal to that of an oxygen molecule at $${47^ \circ }C?$$

Even Carnot engine cannot give $$100\% $$ efficiency because we cannot

Cooking gas containers are kept in a lorry moving with uniform speed. The temperature of the gas molecules inside will