In an electrical circuit, a battery is connected to pass 20C of charge through it in a certain given time. The potential difference between two plates of the battery is maintained at 15V. The workdone by the battery is __________J.

A current of 6A enters one corner P of an equilateral triangle PQR having 3 wires of resistance 2$$\Omega$$ each and leaves by the corner R. The currents i₁ in ampere is _________.

In the given circuit of potentiometer, the potential difference E across AB (10 m length) is larger than E₁ and E₂ as well. For key K₁ (closed), the jockey is adjusted to touch the wire at point J₁ so that there is no deflection in the galvanometer. Now the first battery (E₁) is replaced by second battery (E₂) for working by making K₁ open and K₂ closed. The galvanometer gives then null deflection at J₂. The value of $${{{E_1}} \over {{E_2}}}$$ is $${a \over b}$$, where a = _________.

A cylindrical wire of radius 0.5 mm and conductivity 5 $$\times$$ 10⁷ S/m is subjected to an electric field of 10 mV/m. The expected value of current in the wire will be x³$$\pi$$ mA. The value of x is _________.