What is the de-Broglie wavelength of a neutron in thermal equilibrium with heavy water at a temperature \(T\) (Kelvin) and mass \(m\)?
1. \(\frac{h}{\sqrt{m k T}}\) 2. \(\frac{h}{\sqrt{3 m k T}}\)
3. \(\frac{2 h}{\sqrt{3 m k T}}\) 4. \(\frac{2 h}{\sqrt{m k T}}\)

Subtopic:  De-broglie Wavelength |
 80%
From NCERT
NEET - 2017
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If an electron of mass \(m\) with a de-Broglie wavelength of \(\lambda\) falls on the target in an \(X\text-\)ray tube, the cut-off wavelength \((\lambda_0)\) of the emitted \(X\text-\)ray will be:
1. \(\lambda_0 = \frac{2mc\lambda^2}{h}\)
2. \(\lambda_0 = \frac{2h}{mc}\)
3. \(\lambda_0 = \frac{2m^2c^2\lambda^3}{h^2}\)
4. \(\lambda_0 = \lambda\)

Subtopic:  De-broglie Wavelength |
From NCERT
NEET - 2016
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Photons with energy \(5\) eV are incident on a cathode \(C\) in a photoelectric cell. The maximum energy of emitted photoelectrons is \(2\) eV. When photons of energy \(6\) eV are incident on \(C\), no photoelectron will reach the anode \(A\), if the stopping potential of \(A\) relative to \(C\) is:
1. \(+3\) V
2. \(+4\) V
3. \(-1\) V
4. \(-3\) V

Subtopic:  Einstein's Photoelectric Equation |
 51%
From NCERT
NEET - 2016
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When a metallic surface is illuminated with radiation of wavelength λ, the stopping potential is V. If the same surface is illuminated with radiation of wavelength 2λ, the stopping potential is V4 .The threshold wavelength for metallic surface is:

(a) 5λ                (b)52λ

(c) 3λ                (d) 4λ

Subtopic:  Photoelectric Effect: Experiment |
 65%
From NCERT
NEET - 2016
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An electron of mass m and a photon have the same energy E. Find the ratio of de-Broglie wavelength associated with the electron to that associated with the photon. (c is the velocity of light)

1. E2m1/2

2. c2mE1/2

3. 1c2mE1/2

4. 1cE2m1/2

 

Subtopic:  De-broglie Wavelength |
 58%
From NCERT
NEET - 2016
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A radiation of energy 'E' falls normally on a perfectly reflecting surface. The momentum transferred to the surface is (c=velocity of light)

1. E/c

2. 2E/c

3. 2E/c2

4. E/c2

Subtopic:  Particle Nature of Light |
 59%
NEET - 2015
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A certain metallic surface is illuminated with monochromatic light of wavelength \(\lambda\). The stopping potential for photoelectric current for this light is \(3V_0\). If the same surface is illuminated with light of wavelength \(2\lambda\), the stopping potential is \(V_0\). The photoelectric effect's threshold wavelength for this surface is?
1. \(6\lambda\)
2. \(4\lambda\)
3. \(\dfrac{\lambda}{4}\)
4. \(\dfrac{\lambda}{6}\)
Subtopic:  Einstein's Photoelectric Equation |
 77%
From NCERT
NEET - 2015
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Which of the following figures represents the variation of the particle momentum and the associated de-Broglie wavelength?

1.   2.
3.
4.
Subtopic:  De-broglie Wavelength |
 85%
From NCERT
NEET - 2015
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A photoelectric surface is illuminated successively by monochromatic light of wavelengths \(\lambda\) and \(\frac{\lambda}{2}\). If the maximum kinetic energy of the emitted photoelectrons in the second case is \(3\) times that in the first case, the work function of the surface of the material will be:
(\(h\) = Planck’s constant, \(c\) = speed of light)
1. \(\frac{hc}{2\lambda}\)
2. \(\frac{hc}{\lambda}\)
3. \(\frac{2hc}{\lambda}\)
4. \(\frac{hc}{3\lambda}\)
Subtopic:  Einstein's Photoelectric Equation |
 71%
From NCERT
NEET - 2015
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When the energy of the incident radiation is increased by \(20\%\), the kinetic energy of the photoelectrons emitted from a metal surface increases from \(0.5\) eV to \(0.8\) eV. The work function of the metal will be:
1. \(0.65\) eV
2. \(1.0\) eV
3. \(1.3\) eV
4. \(1.5\) eV
Subtopic:  Einstein's Photoelectric Equation |
 67%
From NCERT
NEET - 2014
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