An iron piece of mass $$200 \mathrm{~g}$$ is kept inside a furnace for some time and then put in a calorimeter of water equivalent $$20 \mathrm{~g}$$ containing $$230 \mathrm{~g}$$ of water at $$20 \mathrm{C}$$. The steady state temperature attained by the mixture is $$60^{\circ}$$. The temperature of the furnace is (Specific heat capacity of iron is $$470 \mathrm{~J~kg}^{-1} \mathrm{C}^{-1}$$ )

An ideal gas changes its state from $$\mathrm{A}$$ to $$\mathrm{C}$$ in two different paths $$\mathrm{ABC}$$ and $$\mathrm{AC}$$. The internal energy of the gas at state $$\mathrm{C}$$ is $$20 \mathrm{~J}$$ and at state $$\mathrm{B}$$ is $$10 \mathrm{~J}$$. Heat supplied to the gas to go from $$\mathrm{B} \rightarrow \mathrm{C}$$ is

If pressure of an ideal gas is increased by keeping temperature constant the kinetic energy will

A cubical box of side $$2 \mathrm{~m}$$ contains helium gas. It was observed that in a time of 1 second, an atom travelling with the root-mean-square speed parallel to one of the edges of the cube, made 250 hits with one of the walls, without any collision with other atoms. The average kinetic energy of the helium gas is Take $$R=\frac{25}{3} \mathrm{~J} / \mathrm{mol}-\mathrm{K}$$ and $$\mathrm{kB}=1.38 \times 10^{-23} \mathrm{JK}{ }^{-1}$$