A capacitor C_1 is charged to a potential difference V. The charging battery is then removed and the capacitor is connected to an uncharged capacitor C_2. The potential difference across the combination is ?

Each corner of a cube of side l has a negative charge, −q. The electrostatic potential energy of a charge q at the centre of the cube is ?

A solid spherical conductor is given a charge. The electrostatic potential of the conductor is ?

A 100 N force acts horizontally on a block of 10 kg placed on a horizontal rough surface of coefficient of friction μ = 0.5. If the acceleration due to gravity (g) is taken as 10 $ms^{−2}$, the acceleration of the block (in $ms^{−2}$ ) is