Question

A circular coil of diameter 2 cm and 100 turns is placed at the centre of a long solenoid of radius 5 cm and 10 turns/cm. The mutual inductance of the two coils will be nearest to:

• A. $40\,\mu\,H$
• B. $4\,\mu\,H$
• C. $40\,mH$
• D. $4\,mH$

Answer 1

Answer: (A)

$40\,\mu\,H$

Answer 2

$M = \mu_0 \mu_1 \, N_2A = 4 \pi \times 10^{-7} \times 1000 \times 100 \times \pi \times (0.01)^2 = 3.95 \times 10^{-5}$ H