The primary coil of a transformer has N turns and is connected to a 120 V a.c. power line. If the secondary coils has 1 000 turns and a terminal voltage of 1 200 volts, what is the value of N?
- 120
-
100
- 1 000
- 1 200
The correct answer is: B
Explanation
For the transformer, V â âŠ
=> V s â âŠs; Vp â âŠp
=> \(\frac{V_p}{V_s} = \frac{âŠ_p}{âŠ_s}\), therefore \(\frac{120}{1200} = \frac{âŠ_p}{1000}\)
therefore âŠ\(_p \times 1200 = 120\times 1000\)
âŠ\(_p = 120\times\frac{1000}{1200}\) = 100
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