A device called a toroid (figure) is often used to create an almost uniform
Channel: Doubtnut
Date: 2020-07-26

A device called a toroid (figure) is often used to create an almost uniform magetic fiedl in some enclosed area. The device consists of a conducting wire wraped around a ring (a torus) made of a non conducting material. For a toroid having `N` closely spaced turns of wire, calculate the magnetic field in the region occupied by the torus, a distasnce `r` from the centre.