Consider the points lying on a straight line joining two fixed opposite charges. Between the charges there is
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(a) No point where electric field is zero |
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(b) Only one point where potential is zero |
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(c) Only one point where electric field is zero |
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(d) a, b |
(d) a, b
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A silver voltameter of resistance 2 ohm and a 3 ohm resistor are connected in series across a cell. If a resistance of 2 ohm is connected in parallel with the voltameter, then the rate of deposition of silver
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(a) Decreases by 25% |
(b) Increases by 25% |
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(c) Increases by 37.5% |
(d) Decreases by 37.5% |
The age of universe is believed to be
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(a) 1 billion years |
(b) 10 billion years |
(c) 10-20 billion years |
(d) 1000 billion years |
The current in a coil of inductance 5 H decreases at the rate of 2 A/s. The induced e.m.f. is
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(a) 2 V |
(b) 5 V |
(c) 10 V |
(d) – 10 V |
Which one of the following is true in photoelectric emission
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(a) Photoelectric current is directly proportional to the amplitude of light of a given frequency |
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(b) Photoelectric current is directly proportional to the intensity of light of a given frequency at moderate intensities |
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(c) Above the threshold frequency, the maximum K.E. of photoelectrons is inversely proportional to the frequency of incident light |
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(d) The threshold frequency depends upon the wavelength of incident light |
Assertion : In the process of photoelectric emission, all the emitted photoelectrons have the same kinetic energy.
Reason : The photon transfers its whole energy to the electron of the atom in photoelectric effect.
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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 assertion is false but reason is true. |
Myopia is due to
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(a) Elongation of eye ball |
(b) Irregular change in focal length |
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(c) Shortening of eye ball |
(d) Older age |