Question

A certain transformer has a turns ratio of 1 and a 0.85 coefficient of coupling. When 2 V ac is applied to the primary, the secondary voltage is

• A. 1.7 V
• B. 0.85 V
• C. 1 V
• D. 0 V

Answer 1

The correct option is A 1.7 V

Coefficient coupling $\eta =0.85$
Input voltage in primary coil $V_p=2V$
Turn ratio $\frac{N_s}{N_p}=1$
Thus output voltage in secondary coil $V_s=\eta \frac{N_s}{N_p}{V}_p$
$⟹V_s=0.85\times 1\times 2=1.7V$