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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What will be the percentage change in the de-Broglie wavelength of the particle if the kinetic energy of the particle is increased to \(16\) times its previous value?
1. \(25\)
2. \(75\)
3. \(60\)
4. \(50\)

Subtopic:  De-broglie Wavelength |
 69%
From NCERT
NEET - 2014
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For photoelectric emission from certain metal, the cut-off frequency is ν. If radiation of frequency 2ν impinges on the metal plate, the maximum possible velocity of the emitted electron will be (m is the electron mass)

1. hν/(2m) 

2. hν/(m) 

3. 2hν/(m) 

4. none of these

Subtopic:  Electron Emission |
 76%
From NCERT
NEET - 2013
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The wavelength \(\lambda_{e}\) of an electron and \(\lambda_{p}\) of a photon of the same energy \(E\) are related as:
1. \(\lambda_p \propto \lambda^2_e\)
2. \(\lambda_p \propto \lambda_e\)
3. \(\lambda_p \propto \sqrt{\lambda_e}\)
4. \(\lambda_p \propto \frac{1}{\sqrt{\lambda_e}}\)

Subtopic:  De-broglie Wavelength |
 54%
From NCERT
NEET - 2013
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A 200W sodium street lamp emits yellow light of wavelength 0.6 μm. Assuming it to be 25% efficient in converting electrical energy to light, the number of photons of yellow light it emits per second is 

(1) 1.5×1020                               

(2) 6×1018

(3) 62×1020                                 

(4) 3×1019

Subtopic:  Electron Emission |
 68%
From NCERT
NEET - 2012
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Monochromatic radiation emitted when electron on hydrogen atom jumps from first excited to the ground state irradiates a photosensitive material. The stopping potential is measured to be 3.57 V.The threshold frequency of the material is:

(1)4×1015Hz                               

(2)5×1015Hz

(3)1.6×1015Hz                           

(4)2.5×1015Hz

Subtopic:  Einstein's Photoelectric Equation |
 64%
From NCERT
NEET - 2012
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An \(\alpha\text-\)particle moves in a circular path of radius \(0.83\) cm in the presence of a magnetic field of \(0.25 ~\text{Wb/m}^2\). The de-Broglie wavelength associated with the particle will be:
1. \(1~\mathring{A}\) 2. \(0.1~\mathring{A}\)
3. \(10~\mathring{A}\) 4. \(0.01~\mathring{A}\)
Subtopic:  De-broglie Wavelength |
 57%
From NCERT
NEET - 2012
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