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Question
The adjacent diagram shows a coil would around a soft iron bar XY. (a) State the polarity at the end X and Y as the switch is pressed. (b) Suggest one way increasing the strength of electromagnet so formed.
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Solution
(a)X-north pole, Y –south pole. (b)By reducing resistance of circuit by mean of rheostat to increase current.
RELATED QUESTIONS
The primary coil of an ideal step-up transformer has 100 turns and the transformation ratio is also 100. The input voltage and power are 220 V and 1100 W, respectively. Calculate the
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(b) current in the primary
(c) a voltage across secondary
(d) current in secondary
(e) power in secondary
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Reason: D.C. changes neither in magnitude nor in direction.
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