Along solenoid of length 9.10 × 10-2 m and cross-sectional area 5.0 × 10-5 m2 contains 6500 turns per meter of length. determine the magnitude of the emf induced in the solenoid when the current in the solenoid changes from 0 to 1.5 a during the time interval from 0 to 0.20 s.

1.8 mV

Explanation:

The total number of turns in the solenoid is

where

n = 6500 is the number of turns per meter of length

is the length of the solenoid

The flux linkage through the solenoid is given by

where

B is the strength of the magnetic field

is the cross-sectional area of the solenoid

The strength of the field in the solenoid is given by

where I is the current.

At the beginning, I = 0, so the field is

And the flux linkage is

Later, the current is I = 1.5 A, so the field in the solenoid is

So, the flux linkage is

So, the change in flux linkage is

And therefore, the emf induced in the solenoid is (in magnitude)

Option A.

Explanation:

In order to create many magnetic field lines, stronger magnets are used so that the cutting of the magnetic field lines will be more frequent creating a higher magnetic induction.