A big drop is formed by coalescing 1000 small droplets of water. The surface energy will become :

A cricket player catches a ball of mass $120 \mathrm{~g}$ moving with $25 \mathrm{~m} / \mathrm{s}$ speed. If the catching process is completed in $0.1 \mathrm{~s}$ then the magnitude of force exerted by the ball on the hand of player will be (in SI unit) :

In a metre-bridge when a resistance in the left gap is $2 \Omega$ and unknown resistance in the right gap, the balance length is found to be $40 \mathrm{~cm}$. On shunting the unknown resistance with $2 \Omega$, the balance length changes by :

A diatomic gas $(\gamma=1.4)$ does $200 \mathrm{~J}$ of work when it is expanded isobarically. The heat given to the gas in the process is :