Question

A wire is turned into circles with 100 turns of radius 35cm. What current be passed through it to produce a magnetic field of 1T at its centre

Answer 1

The magnetic field at the centre of a circular coil having N turns is given by

Here r is the radius of coil and I is the current passing through coil.

now,I = 0.4A , r = 8cm = 0.08 m and

so, B = (4π × 10^-7 × 0.4)/(2 × 0.08) × 100

= 3.14 × 10^-4 T

hence , magnetic field , B = 3.14 × 10^-4 T

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