In moving coil galvanometer, strong horse shoe magnet of concave shaped pole pieces is used to

1. Two identical wires of substances ' $P$ ' and ' $Q$ ' are subjected to equal stretching force along the length. If the elongation of ' $Q$ ' is more than that of ' $P$ ', then

If $W_1, W_2$ and $W_3$ represent the work done in moving a particle from $A$ to $B$ along three different paths 1,2 and 3 (as shown in fig) in the gravitational field of the point mass ' $m$ '. Find the correct relation between ' $W_1$ ', ' $W_2$ ' and ' $W_3$ '

Assuming that the junction diode is ideal, the current in the arrangement shown in figure is