Question

A transformer has 100 turns in the primary coil and carries 8 A current .If input power is 1kW, the number of

turns in secondary coil to have 500 V output will be

• A. 100
• B. 200
• C. 400
• D. 300

Answer 1

Answer: (C)

400

Answer 2

: Here, $N_{P} = 100,I_{P} = 8A,$

Input power, $V_{P}I_{P} = 1kW = 1000W$

$V_{P} = \frac{1000}{I_{P}} = \frac{1000}{8} = 125V$

$V_{s} = 500V$

As ,

$\frac{N_{s}}{N_{P}} = \frac{V_{s}}{V_{p}}\therefore N_{s} = N_{p} \times \frac{V_{s}}{V_{P}} \times 100 \times \frac{500}{125} = 400$