An aeroplane having a wing span of 30 m flies due north with the speed of 170 m/s. Magnetic field $B = 3.6 \times 10^{-5}$ T. The potential difference between the tips of the wings will be

In an LCR series circuit an alternating voltage source of frequency $F$ is connected. The current leads the voltage by $45^\circ$. The value of $L$ is

Given below are the two circuits, choose the correct option.

In a L-R circuit of 4 mH inductance and $3\ \Omega$ resistance, e.m.f. $E = \cos(1000t)$ V is applied. The amplitude of current is