A circular coil of 20 hours and radius 10cm is placed in an uniform magnetic field of `0.17` normal to the plane of the coil if the current in the coil is `5.0A`. What is the
average force on each electron in the coil due to the magnetic field ? The coil is made of copper wire of cross - (a) sectional area `10^(-5) m ^(+2) ` and the free clectron density in copper is given to be about `10^(29)//m^(3) `.

Explanation

(a) Zero, (b) zero, (c) force on each electron is `evB = IB//(nA) = 5 ×x 10^(-25)` N. Note: Answer (c) denotes only the magnetic force.