Q. The coils of a step down transformer have 500 and 5000 turns. In the primary coil an ac of $4\ ampere$ at $2200\ volts$ is sent. The value of the current and potential difference in the secondary coil will be
A) $20\ A,\ 220\ V$
B) $0.4\ A,\ 22000\ V$
C) $40\ A,\ 220\ V$
D) $40\ A,\ 22000\ V$
Explanation
(c) $\frac{N_{p}}{N_{s}} = \frac{V_{p}}{V_{s}} = \frac{i_{s}}{i_{p}}$. The transformer is step-down type, so primary coil will have more turns. Hence
$\frac{5000}{500} = \frac{2200}{V_{s}} = \frac{i_{s}}{4} \Rightarrow V_{s} = 220\ V.\ i_{s} = 40\ amp$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.