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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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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Light of two different frequencies whose photons have energies \(1~\text{eV}\) and \(2.5~\text{eV}\) respectively, successively illuminate a metal whose work function is \(0.5~\text{eV}\). The ratio of the maximum speeds of the emitted electrons will be:
1. \(1:5\)
2. \(1:4\)
3. \(1:2\)
4. \(1:1\)
Subtopic:  Einstein's Photoelectric Equation |
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The ratio of wavelengths of proton and deuteron accelerated by potential \(V_{p}\) and \(V_{d}\) is \(1:\sqrt2.\) Then, the ratio of \(V_{p}\) to \(V_{d}\) will be:
1. \(1:1\)
2. \(\sqrt 2: 1\)
3. \(2:1\) 
4. \(4:1\) 
Subtopic:  De-broglie Wavelength |
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A nucleus of mass \(M,\) initially at rest, splits into two fragments with masses \(\dfrac{M'}{ 3}\) and \(\dfrac{2M'} { 3}\) \((M'<M).\) The ratio of the de-Broglie wavelengths of the two fragments is:
1. \(1:2\) 2. \(2:1\)
3. \(1:1\) 4. \(2:3\)
Subtopic:  De-broglie Wavelength |
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Two beams of monochromatic light of frequencies \(\nu_1\) and \(\nu_2,\) are incident on the surface of a photo-sensitive material. Photo electrons are emitted with maximum kinetic energies \(E_1\) and \(E_2,\) respectively. If the ratio \(E_1:E_2=1:n\), the cut-off frequency for the material is:
1. \(\dfrac{n\nu_1+\nu_2}{n+1}\) 2. \(\dfrac{n\nu_1-\nu_2}{n-1}\)
3. \(\dfrac{n\nu_1-\nu_2}{n+1}\) 4. \(\dfrac{n\nu_1+\nu_2}{n-1}\)
Subtopic:  Einstein's Photoelectric Equation |
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The light rays having photons of energy \(4.2~\text{eV}\) are falling on a metal surface having a work function of \(2.2~\text{eV}.\) The stopping potential of the surface is:
1. \(2~\text{eV}\)
2. \(2~\text{V}\)
3. \(1.1~\text{V}\)
4. \(6.4~\text{V}\)
Subtopic:  Einstein's Photoelectric Equation |
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The threshold frequency of a photoelectric metal is \(\nu_0.\) If the light of frequency \(4\nu_0\) is incident on this metal, then the maximum kinetic energy of emitted electrons will be:
1. \(h\nu_0\) 2. \(2h\nu_0\)
3. \(3h\nu_0\) 4. \(4h\nu_0\)
Subtopic:  Einstein's Photoelectric Equation |
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The de-Broglie wavelength of an electron, when accelerated through a potential difference of \(49~\text{V},\) is nearly:
1. \(0.0175~\text{nm}\)
2. \(0.175~\text{nm}\)
3. \(0.175~\mu\text{m}\)
4. \(0.175~\text{mm}\)
Subtopic:  De-broglie Wavelength |
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The stopping potential \({(V)}\) versus frequency \({(f)}\) of incident radiation is plotted for two photoelectric surfaces \({A}\) and \({B}.\) We can say that the work function of \({A}\):
                                    
1. is equal to that of \({B}\)
2. is greater than that of \({B}\)
3. is smaller than that of \({B}\)
4. cannot be related to that of \({B}\) from the graph
Subtopic:  Einstein's Photoelectric Equation |
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