Question

The magnetic flux density at the centre 100 loop circular coil of 15cm diameter can be the same as to the magnetic flux density at the end of a 200 turns 500cm long solenoid with a current of 3A. estimate the magnitude of current that must flow through circular coil for this to happen (Take permeability of the free space as 4π × 10–7 H/M

Answer 1

Magnetic flux density is measured by $\mu_o \frac NlI$

equating for both we get

$\frac{100}{15}\times I=\frac{200}{500}\times3$

$I=0.18 A$