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Alternating Current — Physics STD 12 Science — Question

Bihar BoardEnglish MediumSTD 12 SciencePhysicsAlternating Current2 Marks
Question
A power transmission line feeds input power at 2300V to a stepdown transformer with its primary windings having 4000 turns. What should be the number of turns in the secondary in order to get output power at 230 V?
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Answer

Input voltage, V1 = 2300
Number of turns in primary coil, n1 = 4000
Output voltage, V2 = 230V
Number of turns in secondary coil = n2
Voltage is related to the number of turns as:
$\frac{\text{V}_1}{\text{V}_2}=\frac{\text{n}_1}{\text{n}_2}$
$\frac{2300}{230}=\frac{4000}{\text{n}_2}$
$\text{n}_2=\frac{4000\times230}{2300}=400$
Hence, there are 400 turns in the second winding.

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