# 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 $\mathrm{}$$$c= 3\times 10^{8}~\text{m/s}$$${}^{}$) 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 $$\overrightarrow v= v_0\hat i$$$\stackrel{}{}$$$( v_o > 0 )$$ enters in an electric field $$\overrightarrow E = -E_0 \hat i$$$$(E_0 = \text{constant}>0)$$ at $$t=0$$. If $$\lambda_0$$${\mathrm{}}_{}$, 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 $$2\lambda$$$\mathrm{}$, 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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