McqMate
Chapters
1. |
E.M.F can be induced in a circuit by |
A. | changing magnetic flux density |
B. | changing area of circuit |
C. | changing the angle |
D. | all of above |
Answer» D. all of above |
2. |
A straight wire of length 0.20 m moves at a steady speed of {{}} 3.0 m s-1 at right angles to the magnetic field of flux density 0.10 T. The e.m.f induced across ends of wire is |
A. | 0.5 V |
B. | 0.06 V |
C. | 0.05 V |
D. | 0.04 V |
Answer» B. 0.06 V |
3. |
By accelerating the magnet inside the coil, the current in it |
A. | increases |
B. | decreases |
C. | remains constant |
D. | reverses |
Answer» A. increases |
4. |
Consequence of motor effect is |
A. | electromagnetic induction |
B. | current |
C. | voltage |
D. | e.m.f |
Answer» A. electromagnetic induction |
5. |
Total number of magnetic field lines passing through an area is called |
A. | magnetic flux density |
B. | magnetic flux |
C. | e.m.f |
D. | voltage |
Answer» B. magnetic flux |
6. |
Magnitude of induced e.m.f is proportional to |
A. | rate of change of current |
B. | rate of change of voltage |
C. | rate of change of magnetic flux linkage |
D. | rate of change of resistance |
Answer» C. rate of change of magnetic flux linkage |
7. |
In transformer, the core is made up of soft iron in order to pass the maximum |
A. | flux |
B. | current |
C. | magnetic flux |
D. | voltage |
Answer» C. magnetic flux |
8. |
For a straight wire, induced current depends upon |
A. | the speed of movement of wire |
B. | the length of wire |
C. | the magnitude of magnetic flux density |
D. | all of above |
Answer» D. all of above |
9. |
In generators, the rate of change of flux linkage is maximum when the coil is moving through the |
A. | vertical position |
B. | horizontal position |
C. | diagonal position |
D. | at an angle of 45° |
Answer» B. horizontal position |
10. |
E.M.F for a coil depends upon |
A. | the cross sectional area |
B. | no. of turns of wire |
C. | the magnitude of magnetic flux density |
D. | all of above |
Answer» D. all of above |
11. |
Currents that flow in circles inside a disc are known as |
A. | eddy currents |
B. | circular currents |
C. | air currents |
D. | alternating curents |
Answer» A. eddy currents |
12. |
When field is parallel to plane of area, magnetic flux through coil is |
A. | zero |
B. | infinite |
C. | 2 |
D. | 5 |
Answer» A. zero |
13. |
Moving a coil in and out of magnetic field induces |
A. | force |
B. | potential difference |
C. | e.m.f |
D. | voltage |
Answer» C. e.m.f |
14. |
Induced current in coil by a magnet turns it into an |
A. | straight wire |
B. | magnet |
C. | ammeter |
D. | electromagnet |
Answer» D. electromagnet |
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