Networks Analysis and Synthesis - Engineering

Q1:

In an unloaded transformer, the fluxes limiting the primary and secondary are 30 mWb and 20 mWb. The coefficient of coupling is

A 1

B 0.1

C 0.33

D 0.67

ANS:D - 0.67

Φ11 = (1 - k) Φ1  φ11 = φ1 - φ2  30 - 20  10 mWb 10 mWb = (1 - k) 30m  0.33 = 1 - k  k = 0.67 .