A long straight wire carrying a current of 25 A rests on a table. Another wire PQ of length 1 m and mass 2.5 g carries the same current but in the opposite direction. The wire PQ is free to slide up and down. To what height will wire PQ rise? (Take μ0 = 4π × 10-7 T·m/A and g = 10 m/s2)

How does the magnetic field at a distance r from an infinitely long wire change if the current is doubled?

The force on a current-carrying conductor in a magnetic field is maximum when _____.

An electron moves vertically downwards into a magnetic field directed towards the right. According to Fleming's Left-Hand Rule, the direction of the magnetic force acting on the electron will be: