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Free Online Mock Physics Multiple Choice Test on AC transformers
Sub Category : AC transformers Test : 4 Time Left :
1) A transformer is employed to reduce 220 V to 11V.The primary draws a current of 5A and the secondary 90A.The efficiency of the transformer is (1) 20% (2) 40% (3) 70% (4) 90%
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2) In a step-up transformer, the turn ratio is 1:2. A Laclanche cell (e.m.f=1.5 V) is connected across the primary. The voltage developed in the secondary would be(1) 3.0 V (2) 0.75 V (3) 1.5 V (4) Zero
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3)The alternating voltage induced in the secondary coil of a transformer is mainly due to
(1) A varying electric field (2) Transformer core (3) Constant current (4) Varying magnetic field
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4) We can reduce eddy currents in the core of a transformer
(1) By increasing turns in secondary (2) By increasing turns in primary (3) By taking thick wire for windings of coils (4) By taking laminated core
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5) A 100%efficient transformer has 100 turns in the primary and 25 turns in its secondary coil.If the current in the secondary coil is 4A, then the current in the primary coil is (1) 16A (2) 8A (3) 4A (4) 1A
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