Two substances $A$ and $B$ of equal mass $m$ are heated at uniform rate of $6\,cal\,s^{-1}$ under similar conditions. A graph between temperature and time is shown in figure. Ratio of heat absorbed $H_A/H_B$ by them for complete fusion is

A cylindrical metal rod of length $L_0$ is shaped into a ring with a small gap as shown. On heating the system

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

An iron ball of mass $0.2\,kg$ is heated to $10\,^oC$ and put into a block of ice at $0\,^oC.$ $25\,g$ of ice melts. If the latent heat of fusion of ice is $80\,cal/g,$ then the specific heat of iron in $cal/g\,^oC$ is

A bimetallic strip consists of metals $X$  and $Y.$  It is mounted rigidly at the base as shown in the figure. The metal $X$  has a higher coefficient of expansion as compared to that for metal $Y.$  When the bimetallic strip is placed in a cold bath ?