Question

A transformer has 120 turns in the primary coil and carries 5A current. Input power is one kilowatt. To have 560 V output, the number of turns in secondary coil will be

• A. \(168\)
• B. \(200\)
• C. \(336\)
• D. \(400\)

Hint:

Find the primary voltage from \(P=V_pI_p\), then use the turns ratio.

Answer 1

The Correct Option is C

Step 1: Find the voltage ratio
$V_p=\dfrac{P}{I_p}=200$ V, so $\dfrac{V_s}{V_p}=\dfrac{560}{200}=2.8$.

Step 2: Scale the turns
$N_s=2.8\times120=336$, option (C).

Final Answer:
The secondary turns number 336, option (C). \[ \boxed{336} \]