Moving Charges and Magnetism

Torque required to hold a small circular coil of 10 turns, area of \(2 \times 10^{-4} \mathrm{~m}^2\) area of carrying 0.5 A current in the middle of a long solenoid of \(10^3\) turns per metre carrying \(3 \mathrm{~A}\) current, with its a...

A long thin hollow metallic cylinder of radius
R has a current i ampere. The magnetic
induction B away from the axis at a distance r
from the axis varies as shown in

In which of the following case no force
exerted by a magnetic field on a charge?

The magnetic field, of a given length of wire
for single turn coil, at its centre is B, then its
value for two turns coil for the same wire is

In a co-axial, straight cable, the central conductor and the outer conductor carry equal currents in opposite directions. The magnetic field is zero