Question

During a 72-ms interval, a change in the current in a primary coil occurs. This change leads to the appearance of a 6.0-mA current in a nearby secondary coil. The secondary coil is part of a circuit in which the resistance is 12 Ω. The mutual inductance between the two coils is 3.2 mH. What is the change in the primary current?

Answer 1

so change in primary current is 1.620 A

Step-by-step explanation:

Given data

current I =6.0-mA = 6 × 10^(-3) A

resistance R = 12 Ω

mutual inductance M = 3.2 mH = 3.2 × 10^(-3) H

dt = 72-ms = 72 × 10^-(3) s

to find out

change in the primary current

solution

we know that

Electric and magnetic fields in secondary coil = mutual inductance × change in primary current / dt ............1

and we know also that Electric and magnetic fields in secondary coil = resistance × current

so = 6 × 10^(-3) × 12 = 72 × 10^(-3) volts

so that we say

change in primary current from equation 1

change in primary current = Electric and magnetic fields in secondary coil × dt / mutual inductance

change in primary current = 72 × 10^(-3) × 72 × 10^(-3) / 3.2 × 10^(-3)

change in primary current = 1.620

so change in primary current is 1.620 A