- ✓South to North pole
- BNorth to South pole
- CEast to West direction
- DWest to East direction
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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 |
A freshly prepared radioactive sample of half- life 1 hour emits radiations that are 128 times as intense as the permissible safe limit. The minimum time after which this sample can be safely used is
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(a) 14 hours |
(b) 7 hours |
(c) 128 hours |
(d) 256 hours |
The frequency and work function of an incident photon are n and
. If n0 is the threshold frequency then necessary condition for the emission of photo electron is
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(a) |
(b) v = |
(c) |
(d) None of these |
A double convex lens has two surfaces of equal radii R and refractive index $\mu=1.5$ We have,
How can we explain the reddish appearance of sun at sunrise or sunset?
The measurement of voltmeter in the following circuit is
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(a) 2.4 V |
(b) 3.4 V |
(c) 4.0 V |
(d) 6.0 V |