JEE PYQ: Electromagnetic Induction Question 21
Question 21 - 2019 (09 Jan Shift 2)
A power transmission line feeds input power at 2300 V to a step down transformer with its primary windings having 4000 turns. The output power is delivered at 230 V by the transformer. If the current in the primary of the transformer is 5 A and its efficiency is 90%, the output current would be:
(1) 50 A
(2) 45 A
(3) 35 A
(4) 25 A
Show Answer
Answer: (2)
Solution
Efficiency $\eta = \frac{P_{\text{out}}}{P_{\text{in}}} = \frac{V_s I_s}{V_p I_p}$. $0.9 = \frac{230 \times I_s}{2300 \times 5}$. $I_s = 0.9 \times 50 = 45$ A.
BETA
