Electromagnetic Induction

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Question

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Question 1 : The coupling co-efficient of the perfectly coupled coils is ___________
1. one
2. zero
3. infinite
4. slightly more than one
Answer
8887

Question 2 : One henry is equal to ____________
1. weber/ampere
2. weber/Volt
3. weber ampere
4. None of these
Answer
8888

Question 3 : The magnetic field is parallel to a surface, then the magnetic flux through the surface is _____________
1. zero
2. infinite
3. small but not zero
4. large but not infinite
Answer
8889

Question 4 : A transformer is used to light 100 W and 110 V lamp from a 220 V mains. If the main current is 0.5 A. Then the efficiency of the transformer is
1. 90%
2. 80%
3. 50%
4. 10%
Answer
8890

Question 5 : The magnetic flux (∅) linked with a coil is related to the number of turns (N) of the coil as _______
1. f ∝ N
2. f ∝ N^-1
3. f ∝ N^-2
4. f ∝ N²
Answer
8891