Question

Two coils P and Q are kept near each other. When no current flows through coil P and current increases in coil Q at the rate 10 A/s, the e.m.f. in coil P is 20 mV. When coil Q carries no current and current of 1.6 A flows through coil P, the magnetic flux linked with the coil Q is ____________.

Options

• 1.4 mWb

• 2.2 mWb

• 3.2 mWb

• 4.9 mWb

Answer 1

Two coils P and Q are kept near each other. When no current flows through coil P and current increases in coil Q at the rate 10 A/s, the e.m.f. in coil P is 20 mV. When coil Q carries no current and current of 1.6 A flows through coil P, the magnetic flux linked with the coil Q is 3.2 mWb.

Explanation:

 `phi_Q= M I_P`

But

`abs(e_p)= M (dl_Q)/dt`

M = `(e_P xx dt)/(dl_Q)`

`therefore  phi_ Q= (e_P xx dt)/ (dl_Q) xx I_P`

`phi_P = (20 xx 10^-3)/ 10 xx 1.6`

`phi_P= 3.2 xx 10^-3` Wb = 3.2 mWb