Consider a beam of electrons (each electron with energy \(E_0\)) incident on a metal surface kept in an evacuated chamber. Then:

1. no electrons will be emitted as only photons can emit electrons.
2. electrons can be emitted but all with energy, \(E_0.\)
3. electrons can be emitted with any energy, with a maximum of \({E}_0-\phi\) (\(\phi\) is the work function).
4. electrons can be emitted with any energy, with a maximum \(E_0.\)

Subtopic:  Electron Emission |
Level 4: Below 35%
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The threshold frequency for a photosensitive metal is \(3.3\times10^{14}~\text{Hz}.\) If the light of frequency \(8.2\times10^{14}~\text{Hz}\) is incident on this metal, the cutoff voltage for the photoelectric emission will be:

1. \(1~\text{V}\) 2. \(2~\text{V}\)
3. \(3~\text{V}\) 4. \(5~\text{V}\)
Subtopic:  Einstein's Photoelectric Equation |
 72%
Level 2: 60%+
AIPMT - 2011
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A light of wavelength \(\lambda \) is incident on the metal surface and the ejected fastest electron has speed \(v.\) If the wavelength is changed to \(\frac{3\lambda}{4},\) then the speed of the fastest emitted electron will be:

1. smaller than \(\sqrt{\frac{4}{3}}v\)
2. greater than \(\sqrt{\frac{4}{3}}v\)
3. \(2v\)
4. zero
Subtopic:  Einstein's Photoelectric Equation |
 71%
Level 2: 60%+
AIPMT - 1998
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The work functions for metals \(A,B,\) and \(C\) are respectively \(1.92\) eV, \(2.0\) eV, and \(5\) eV. According to Einstein's equation, the metals that will emit photoelectrons for a radiation of wavelength \(4100~\mathring{A}\) is/are:

1. None 2. \(A\) only
3. \(A\) and \(B\) only 4. All the three metals
Subtopic:  Einstein's Photoelectric Equation |
 81%
Level 1: 80%+
AIPMT - 2005
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A photosensitive metallic surface has a work function of \(h\nu_0\). If photons of energy \(2h\nu_0\) fall on this surface, the electrons come out with a maximum velocity of \(4\times10^{6}\) m/s. When the photon energy is increased to \(5h\nu_0\), then the maximum velocity of photoelectrons will be:
1. \(2\times 10^7~\text{m/s}\)
2. \(2\times 10^6~\text{m/s}\)
3. \(8\times 10^5~\text{m/s}\)
4. \(8\times 10^6~\text{m/s}\)

Subtopic:  Einstein's Photoelectric Equation |
 80%
Level 1: 80%+
AIPMT - 2005
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An electron is accelerated from rest through a potential difference of \(V\) volt. If the de Broglie wavelength of an electron is \(1.227\times10^{-2}~\text{nm}.\) What will be its potential difference?

1. \(10^{2}~\text{V}\) 2. \(10^{3}~\text{V}\)
3. \(10^{4}~\text{V}\) 4. \(10^{5}~\text{V}\)
Subtopic:  De-broglie Wavelength |
 60%
Level 2: 60%+
NEET - 2020
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The de-Broglie wavelength of a particle accelerated by a \(150\) volt potential difference is \(10^{-10}\) m. What will its wavelength be if it is accelerated by a \(600\) volt potential difference?
1. \(0.25~\mathring{A}\)
2. \(0.5~\mathring{A}\)
3. \(1.5~\mathring{A}\)
4. \(2~\mathring{A}\)

Subtopic:  De-broglie Wavelength |
 79%
Level 2: 60%+
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In an experiment of the photoelectric effect, the wavelength of incident radiation is λ. The wavelength of incident radiation is reduced to 13rd of initial value and the maximum kinetic energy of photoelectron is observed to be n times the previous value. What will be the threshold wavelength for the metal plate?

1. \(\dfrac{n-1}{n-3} \lambda \) 2. \(\dfrac{n}{n-3} \lambda \)
3. \(\dfrac{n-3}{n-1} \lambda \) 4. \(\dfrac{n+1}{n-3} \lambda\)
Subtopic:  Einstein's Photoelectric Equation |
 73%
Level 2: 60%+
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A source \(S_1\) is producing, \(10^{15}\) photons per sec of wavelength \(5000~\mathring{A}.\) Another source \(S_2\) is producing \(1.02\times 10^{15}\) photons per second of wavelength \(5100~\mathring{A}.\) Then the ratio of the power of \(S_2\) to the power of \(S_1\) is equal to:
1. \(1.00\) 2. \(1.02\)
3. \(1.04\) 4. \(0.98\)
Subtopic:  Particle Nature of Light |
 77%
Level 2: 60%+
AIPMT - 2010
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Electrons used in an electron microscope are accelerated by a voltage of \(25\) kV. If the voltage were increased to \(100\) kV, then the de-Broglie wavelength associated with the electrons would:
1. decrease by \(2\) times
2. decrease by \(4\) times
3. increase by \(4\) times
4. increase by \(2\) times
Subtopic:  De-broglie Wavelength |
 80%
Level 1: 80%+
AIPMT - 2011
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