A person standing between two parallel cliffs fires a gun and hears two echoes, first echo after 1 second and the second echo after 3 second. The distance between the two cliffs is (Velocity of sound $=340 \mathrm{~m} / \mathrm{s}$ )

A series combination of 10 capacitors, each of value ' $\mathrm{C}_1$ ' is charged by a source of potential difference ' 4 V '. When another parallel combination of 8 capacitors, each of value ' $\mathrm{C}_2$ ' is charged by a source of potential difference ' V ', it has the same total energy stored in it as in the first combination. The value of ' $\mathrm{C}_2$ ' is

A solid sphere and thin walled hollow sphere have same mass and same material. Which of them have greater moment of inertia about their diameter?

[ $\mathrm{I}_{\mathrm{h}}=$ moment of inertia of hollow sphere about an axis coinciding with its diameter, $\mathrm{I}_5=$ moment of inertia of solid sphere about an axis coinciding with its diameter]

The total charge induced in a conducting loop when it is moved in a uniform magnetic field depends on