Question

A closely wound solenoid 80 cm long has 5 layers of windings of 400 terns each. The diameter of the solenoid is 1.8 cm. It the current carried is 8.0 A, estimate the magnitude of B inside the solenoid near its centre.

Answer 1

The length of solenoid, l=80 cm =0.8 m
Number of layers =5
Number of turns per layer =400
Diameter of solenoid =1.8 cm
Current in solenoid =I=8 A
`therefore` The total number of turns `N=400xx5=2000`
and no. of turns/length, `n=(2000)/(0.8)=2500`
The magnitude of magnetic field inside the solenoid
`B=mu_(0)nI=4xx3.14 10^(-7)xx2500xx8`
`=2.5xx10^(-2)T`