The photoelectric threshold wavelength of silver is \(3250\times 10^{-10}~\text{m}\). What will be the velocity of the electron ejected from a silver surface by the ultraviolet light of wavelength \(2536\times 10^{-10}~\text{m}\)? (Given \(h= 4.14\times 10^{-15}~\text{eVs}\) and \(c= 3\times 10^{8}~\text{m/s}\))
1. \(\approx 0.6\times 10^{6}~\text{m/s}\)
2. \(\approx 61\times 10^{3}~\text{m/s}\)
3. \(\approx 0.3\times 10^{6}~\text{m/s}\)
4. \(\approx 0.3\times 10^{5}~\text{m/s}\)

Subtopic:  Einstein's Photoelectric Equation |
From NCERT
NEET - 2017
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An electron of mass m with an initial velocity \(\overrightarrow v= v_0\hat i\)\( ( v_o > 0 ) \) enters in an electric field \(\overrightarrow E = -E_0 \hat i\)\((E_0 = \text{constant}>0)\) at \(t=0\). If \(\lambda_0\), is its de-Broglie wavelength initially, then what will be its de-Broglie wavelength at time \(t\)?
1. \(\frac{\lambda_0}{\left(1+ \frac{eE_0}{mv_0}t\right)}\)
2. \(\lambda_0\left(1+ \frac{eE_0}{mv_0}t\right)\)
3. \(\lambda_0 t\)
4. \(\lambda_0\)

Subtopic:  De-broglie Wavelength |
 67%
From NCERT
NEET - 2018
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When the light of frequency \(2\nu_0\) (where \(\nu_0\) is threshold frequency), is incident on a metal plate, the maximum velocity of electrons emitted is \(v_1\). When the frequency of the incident radiation is increased to \(5\nu_0,\) the maximum velocity of electrons emitted from the same plate is \(v_2.\) What will be the ratio of \(v_1\) to \(v_2\)?

1. \(1:2\) 2. \(1:4\)
3. \(4:1\) 4. \(2:1\)
Subtopic:  Einstein's Photoelectric Equation |
 72%
From NCERT
NEET - 2018
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​​​When a metallic surface is illuminated with radiation of wavelength \(\lambda\), the stopping potential is \({V}\). If the same surface is illuminated with radiation of wavelength \(2\lambda\), the stopping potential is \(\frac{{V}}{4}\). The threshold wavelength for the metallic surface is:
1. \(5\lambda\)
2. \(\frac{5}{2} \lambda\)
3. \(3\lambda\)
4. \(4\lambda\)
Subtopic:  Einstein's Photoelectric Equation |
 76%
From NCERT
NEET - 2016
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An electron of mass \(m\) and a photon have the same energy \(E.\) The ratio of de-Broglie wavelengths associated with them is:
(\(c\) is the velocity of light)


1. \( \sqrt{\left(\frac{{E}}{2 {m}}\right)}\)
2. \({c}\sqrt{(2 {mE})}\)
3. \( \frac{1}{{c}}\sqrt{\left(\frac{2 m}{E}\right)}\)
4. \(\frac{1}{{c}}\sqrt{\left(\frac{{E}}{2 {m}}\right)}\)
Subtopic:  De-broglie Wavelength |
 69%
From NCERT
NEET - 2016
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A photoelectric surface is illuminated successively by the monochromatic light of wavelength \(\lambda\) 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 mineral is:
[\(h\) = Plank’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 |
 72%
From NCERT
NEET - 2015
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Light of wavelength \(500~\text{nm}\) is incident on metal with work function \(2.28~\text{eV}\). The de-Broglie wavelength of the emitted electron is:

1. \(< 2.8\times 10^{-10}~\text{m} \) 2. \(< 2.8\times 10^{-9}~\text{m}\)
3. \(\geq 2.8\times 10^{-9}~\text{m}\) 4. \(\leq 2.8\times 10^{-12}~\text{m}\)
Subtopic:  De-broglie Wavelength |
 61%
From NCERT
NEET - 2015
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Radiation of energy \(E\) falls normally on a perfectly reflecting surface. The momentum transferred to the surface is:
(\(c\) = velocity of light)
1. \(E \over c\)
2. \(2E \over c\)
3. \(2E \over c^2\) 
4. \(E \over c^2\)

Subtopic:  Particle Nature of Light |
 72%
From NCERT
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 a light of wavelength \(2\lambda\), the stopping potential is \(V_0\). The threshold wavelength for this surface for the photoelectric effect is:
1. \(6\lambda\)
2. \(4\lambda\)
3. \(\frac{\lambda}{4}\)
4. \(\frac{\lambda}{6}\)
Subtopic:  Einstein's Photoelectric Equation |
 80%
From NCERT
NEET - 2015
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Which of the following figures represent the variation of the particle momentum and the associated de-Broglie wavelength?

1.   2.
3.   4.  
Subtopic:  De-broglie Wavelength |
 87%
From NCERT
NEET - 2015
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