How many $sec$ are required to raise the temperature of $1\, litre$ of water from $20\,^oC$ to $40\,^oC$ using an $836\, W$ heater?

Which of the following substances has the maximum specific heat capacity?

Write the old and new definition of calorie.

If the temperature scale is changed from $^\circ C$ to $^\circ F$, the numerical value of specific heat will

$A$ lead bullet of mass $10 \ g$ travelling at $300 \ m/s$ strikes against a block of wood and comes to rest. Assuming $50\%$ of heat is absorbed by the bullet,the increase in its temperature is (Specific heat of lead $= 150 \ J/kg \cdot ^{\circ}C$) (in $^{\circ}C$)

The density of a material $A$ is $1500 \ kg/m^3$ and that of another material $B$ is $2000 \ kg/m^3$. It is found that the heat capacity of $8$ volumes of $A$ is equal to the heat capacity of $12$ volumes of $B$. The ratio of specific heats of $A$ and $B$ will be