If the intensity of radiation incident on a photocell is increased four times keeping frequency constant, then the number of photoelectrons and energy of photoelectrons emitted become: 
1. four times, doubled
2. doubled, remains unchanged
3. remains unchanged, doubled
4. four times, remains unchanged

Subtopic:  Electron Emission |
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Which of the following statements about photons is incorrect?

1. The rest mass of a photon is zero.
2. The momentum of a photon is given by \(h\nu/c.\)
3. The energy of a photon is \(h\nu.\)
4. Photons do not exert any pressure.
Subtopic:  Particle Nature of Light |
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In the de-Broglie equation, wavelength \(\mathit{\lambda}\) depends upon mass \(m\) and energy \(E\) according to the relation represented as:
1. \(mE^{1/2}\)
2. \(m^{-1/2}E^{1/2}\)
3. \(m^{-1/2}E^{-1/2}\)
4. \(m^{1/2}E^{-1/2}\)
Subtopic:  De-broglie Wavelength |
 86%
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Ultraviolet photons, each of energy \(20~\text{eV},\) are incident onto a gas of \(\mathrm {H}\)-atoms, causing the emission of electrons. The kinetic energy of the emitted electrons has the value:
1. \(6.4~\text{eV}\)
2. \(7.2~\text{eV}\)
3. \(3.2~\text{eV}\)
4. \(13.6~\text{eV}\)
Subtopic:  Electron Emission |
 68%
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When two monochromatic lights of frequency, \(\nu\) and \(\dfrac{\nu}{2}\) are incident on a photoelectric metal, their stopping potential becomes \(\dfrac{V_{s}}{2}\) and \(V_s\), respectively. The threshold frequency for this metal is:
1. \(\dfrac{3}{2} \nu\) 2. \(2\nu\)
3. \(3\nu\) 4. \(\dfrac{2}{3} \nu\)
Subtopic:  Einstein's Photoelectric Equation |
 71%
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NEET - 2022
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In a photoelectric experiment, blue light is capable of ejecting a photoelectron from a specific metal while green light is not able to eject a photoelectron. Ejection of photoelectrons is also possible using light of the colour:

1. yellow 2. red
3. violet 4. orange
Subtopic:  Photoelectric Effect: Experiment |
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NEET - 2022
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Given below are two statements: 
Assertion (A): The work function of aluminium is \(4.2~\text{eV}\). Emission of electrons will not be possible if two photons, each of energy \(2.5~\text{eV}\), strike an electron of aluminium.
Reason (R): For photoelectric emission, the energy of each photon should be greater than the work function of aluminium.
 
1. Both (A) and (R) are True and (R) is the correct explanation of (A).
2. Both (A) and (R) are True but (R) is not the correct explanation of (A).
3. (A) is True but (R) is False.
4. Both (A) and (R) are False.
Subtopic:  Photoelectric Effect: Experiment |
 87%
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Given below are two statements:
Assertion (A): The photoelectric effect demonstrates the wave nature of light.
Reason (R): The number of photoelectrons emitted is proportional to the frequency of light.
 
1. Both (A) and (R) are True and (R) is the correct explanation of (A).
2. Both (A) and (R) are True but (R) is not the correct explanation of (A).
3. (A) is True but (R) is False.
4. Both (A) and (R) are False.
Subtopic:  Particle Nature of Light |
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A monochromatic source of light emits \(50~\text{W}\) at a wavelength of \(400~\text{nm}.\) The number of photons emitted per second is approximately (take \({hc} = 1240~\text{eV-nm}\)):
1. \(10^{20}\) 
2. \(10^{25}\)
3. \(10^{30}\)
4. \(10^{40}\)
Subtopic:  Particle Nature of Light |
 81%
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The threshold frequency for a photosensitive metal is \(\nu_{0}\). When photons of frequency \(2\nu_{0}\) are incident on a photosensitive plate, the cut-off potential is \(V_{0}\). What will be the cut-off potential, when the light of frequency \(5\nu_{0}\) is incident on it?
1. \(V_{0}\)
2. \(2V_{0}\)
3. \(4V_{0}\)
4. \(5V_{0}\)
Subtopic:  Einstein's Photoelectric Equation |
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