NEET Physics — Thermal Properties of Matter

A gas at \( 1.9 \, \text{atm} \) and \( 67^\circ \text{C} \) occupies \( 6.5 \, \text{L} \). If the pressure is increased to \( 2.5 \, \text{atm} \) and temperature raised to \( 117^\circ \text{C} \), what is the new volume?

A steel disc of radius \( 25 \, \text{cm} \) at \( 30^\circ \text{C} \) is heated to \( 130^\circ \text{C} \). What is the increase in its area? (\( \alpha_l = 1.2 \times 10^{-5} \, \text{K}^{-1} \))

What is the heat required to raise the temperature of \( 0.5 \, \text{kg} \) of copper from \( 30^\circ \text{C} \) to \( 80^\circ \text{C} \)? (Specific heat of copper = \( 386 \, \text{J kg}^{-1} \text{K}^{-1} \))

A \( 0.25 \, \text{kg} \) iron block at \( 150^\circ \text{C} \) is dropped into \( 1.5 \, \text{kg} \) of water at \( 30^\circ \text{C} \). What is the final temperature? (Specific heat of iron = \( 450 \, \text{J kg}^{-1} \text{K}^{-1} \), water = \( 4186 \, \text{J kg}^{-1} \text{K}^{-1} \))

How much heat is needed to melt \( 0.4 \, \text{kg} \) of lead at its melting point of \( 328^\circ \text{C} \)? (Latent heat of fusion of lead = \( 0.25 \times 10^5 \, \text{J kg}^{-1} \))