Question

A choke coil of negligible resistance takes current of 8 Amp when connected to a 200 V and 50 Hz supply. What current would it take if the new supply is 150 V and 80 Hz?

• A. 4.8 A
• B. 3.75 A
• C. 2.4 A
• D. 7.2 A

Answer 1

The correct option is B 3.75 A

$i=\frac{V}{X_L}\frac{i_1}{i_2}=\frac{V_1}{V_2}\left(\frac{X_{L_2}}{X_{L_1}}\right)$
$\frac{8}{i_2}=\frac{200}{150}\times \frac{w_{2}L}{w_{1}L}=\frac{200}{150}\times \frac{80}{50}$
$i_2=\frac{8\times 150\times 50}{200\times 80}=3.75A$