Liquid oxygen at $50 \, K$ is heated to $300 \, K$ at a constant pressure of $1 \, atm$. If the rate of heating is constant,which of the following graphs represents the variation of temperature with time?

$A$ thermally insulated vessel contains some water at $0^{\circ}C$. The vessel is connected to a vacuum pump to pump out water vapour. This results in some water getting frozen. It is given that the latent heat of vaporization of water at $0^{\circ}C = 21 \times 10^5 \text{ J/kg}$ and the latent heat of fusion of water $= 3.36 \times 10^5 \text{ J/kg}$. The maximum percentage amount of water that will be solidified in this manner will be ...... $\%$

$A$ copper block of mass $2.5\; kg$ is heated in a furnace to a temperature of $500\; ^{\circ}C$ and then placed on a large ice block. What is the maximum amount of ice (in $kg$) that can melt? (Specific heat of copper $= 0.39\; J\; g^{-1}\; K^{-1}$; heat of fusion of water $= 335\; J\; g^{-1}$)

$A$ lead bullet moving with velocity '$v$' strikes a wall and stops. If $50\%$ of its energy is converted into heat,then the increase in temperature is ($s =$ specific heat of lead,$J =$ mechanical equivalent of heat).

How much energy will be released by cooling $1\,kg$ of water up to a temperature of $10\,^{\circ}C$?

What type of changes occur in an object by heating it?