- A$\frac{1}{100}\text{second}$
- B100 second
- C50 second
- DNone of these
Explanation:
In India, the frequency of AC voltage is 50 Hz.
It means 50 waves will be produced in 1 s.
In one wave, the direction is changed 2 times.
Thus, in 50 waves, the direction will be altered 50 × 2 = 100 times.
i.e. the direction is changed 100 times in 1 s.
Thus the direction is changed in every $\frac{1}{100}\text{second}$
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In the case of bar magnet, lines of magnetic induction
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(a) Start from the north pole and end at the south pole |
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(b) Run continuously through the bar and outside |
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(c) Emerge in circular paths from the middle of the bar |
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(d) Are produced only at the north pole like rays of light from a bulb |
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(a) 4 : 1 |
(b) 1 : 4 |
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Assertion : An N-type semiconductor has a large number of electrons but still it is electrically neutral.
Reason : An N-type semiconductor is obtained by doping an intrinsic semiconductor with a pentavalent impurity.
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(a) If both assertion and reason are true and the reason is the correct explanation of the assertion. |
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(b) If both assertion and reason are true but reason is not the correct explanation of the assertion. |
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(c) If assertion is true but reason is false. |
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(d) If the assertion and reason both are false. |
When a plane polarised light is passed through an analyser and analyser is rotated through 90°, the intensity of the emerging light
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(a) Varies between a maximum and minimum |
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(b) Becomes zero |
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(d) Varies between a maximum and zero |