The amount of heat required to change $1 \, g$ of ice at $0^\circ C$ into water at $100^\circ C$ is ............ $cal$.

Steam is passed into $22\, g$ of water at $20^{\circ}C$. The mass of water that will be present when the water acquires a temperature of $90^{\circ}C$ is ............ $g$ (Latent heat of steam is $540\, cal/g$) (in $, g$)

If $60 \%$ of the kinetic energy of water falling from a $210 \ m$ high waterfall is converted into heat,the rise in temperature of the water at the bottom of the fall is nearly (specific heat of water $= 4.2 \times 10^3 \ J \ kg^{-1} \ K^{-1}$ and $g = 10 \ m/s^2$):

$A$ lead bullet at $27\ ^oC$ just melts when stopped by an obstacle. Assuming that $25\%$ of heat is absorbed by the obstacle,the velocity of the bullet at the time of striking is ....... $m/s$. (Melting point of lead $= 327\ ^oC$,specific heat of lead $= 0.03\ cal/g\ ^oC$,latent heat of fusion of lead $= 6\ cal/g$,and $J = 4.2\ J/cal$)

$A$ pellet of mass $m$ and specific heat capacity $c$ fired from an air gun hits a steel plate with speed $v$. During the impact,$50\%$ of the pellet's kinetic energy is converted to thermal energy in it. The rise in the temperature of the pellet is

$A$ boy is able to chew $20 \, g$ of ice cream in $5 \, minutes$. Calculate the power of the boy in horse power $(HP)$. (Assume the latent heat of fusion of ice is $80 \, cal/g$ and $1 \, cal = 4.2 \, J$).