Question

Two coils P and Q are kept near each other. When no current flows through coil P and current increase in coil Q at the rate 10A/s, the emf in coil P is 15mV. When coil Q carries no current and current of 1. 8A flows through coil P, the magnetic flux linked with the coil Q is ______.

Options

• 1.4 m Wb

• 2.2 m Wb

• 2.7 m Wb

• 2.9 m Wb

Answer 1

Two coils P and Q are kept near each other. When no current flows through coil P and current increase in coil Q at the rate 10A/s, the emf in coil P is 15mV. When coil Q carries no current and current of 1. 8A flows through coil P, the magnetic flux linked with the coil Q is 2.7 m Wb.

Explanation:

Induced emf in coil P

|e_p| = M. `"dI"_"Q"/"dt"`

Putting e_p = 15 m V = 15 × 10^-2 V

and `"dI"_"Q"/"dt"` = 10 A/s

15 × 10^-3 = M × 10

or, M = 15 × 10^-4 H

Magnetic flux linked with coil Q

Φ_Q = MI_p = 15 × 10^-4 × 1.8    [∵ I_p = 1.8 A]

= 27.0 × 10^-4

= 2.7 × 10^-3

= 2.7 m Wb