# The number of photons per second on an average emitted by a source of monochromatic light of wavelength $$600~\text{nm}$$, when it delivers the power of $$3.3\times 10^{-3}$$ watt will be: $$(h = 6.6\times10^{-34}~\text{J-s})$$ 1. $$10^{16}$$ 2. $$10^{15}$$ 3. $$10^{18}$$ 4. $$10^{17}$$

Subtopic: Â Particle Nature of Light |
Â 64%
From NCERT
NEET - 2021
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An electromagnetic wave of wavelength $$\lambda$$ is incident on a photosensitive surface of negligible work function. If '$$m$$' is the mass of photoelectron emitted from the surface and $$\lambda_d$$ is the de-Broglie wavelength, then:
1. $$\lambda=\left(\frac{2 {mc}}{{h}}\right) \lambda_{{d}}^2$$
2. $$\lambda=\left(\frac{2 {h}}{{mc}}\right) \lambda_{{d}}^2$$
3. $$\lambda=\left(\frac{2 {m}}{{hc}}\right) \lambda_{{d}}^2$$
4. $$\lambda_{{d}}=\left(\frac{2 {mc}}{{h}}\right) \lambda^2$$

Subtopic: Â De-broglie Wavelength |
Â 55%
From NCERT
NEET - 2021
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An electron with $$144~\text{eV}$$ of kinetic energy has a de-Broglie wavelength that is very similar to?
1. $$102\times10^{-3}~\text{nm}$$
2. $$102\times10^{-4}~\text{nm}$$
3. $$102\times10^{-5}~\text{nm}$$
4. $$102\times10^{-2}~\text{nm}$$

Subtopic: Â De-broglie Wavelength |
Â 52%
From NCERT
NEET - 2020
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When two monochromatic lights of frequency, $$\nu$$ and $$\frac{\nu}{2}$$ are incident on a photoelectric metal, their stopping potential becomes $$\frac{V_{s}}{2}$$ and $$V_s$$, respectively. The threshold frequency for this metal is:
 1 $$\frac{3}{2} \nu$$ 2 $$2\nu$$ 3 $$3\nu$$ 4 $$\frac{2}{3} \nu$$
Subtopic: Â Einstein's Photoelectric Equation |
Â 69%
From NCERT
NEET - 2022
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The graph which shows the variation of de Broglie wavelength $$(\lambda)$$ of a particle and its associated momentum $$(p)$$ is:

 1 2 3 4
Subtopic: Â De-broglie Wavelength |
Â 83%
From NCERT
NEET - 2022
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The de-Broglie wavelength of the thermal electron at $$27^\circ \text{C}$$ is $$\lambda.$$ When the temperature is increased to $$927^\circ \text{C},$$ its de-Broglie wavelength will become:
1. $$2\lambda$$
2. $$4\lambda$$
3. $$\frac\lambda2$$
4. $$\frac\lambda4$$

Subtopic: Â De-broglie Wavelength |
Â 60%
From NCERT
NEET - 2022
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In a photoelectric experiment, blue light is capable of ejecting a photoelectron from a specific metal while green light is not able to eject a photoelectron. Ejection of photoelectrons is also possible using light of the colour:
1. yellow
2. red
3. violet
4. orange

Subtopic: Â Photoelectric Effect: Experiment |
Â 82%
From NCERT
NEET - 2022
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The light rays having photons of energy $$4.2~\text{eV}$$ are falling on a metal surface having a work function of $$2.2~\text{eV}.$$ The stopping potential of the surface is:
 1 $$2~\text{eV}$$ 2 $$2~\text{V}$$ 3 $$1.1~\text{V}$$ 4 $$6.4~\text{V}$$
Subtopic: Â Einstein's Photoelectric Equation |
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From NCERT
NEET - 2022
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The threshold frequency of a photoelectric metal is $$\nu_0.$$ If the light of frequency $$4\nu_0$$ is incident on this metal, then the maximum kinetic energy of emitted electrons will be:
 1 $$h\nu_0$$ 2 $$2h\nu_0$$ 3 $$3h\nu_0$$ 4 $$4h\nu_0$$
Subtopic: Â Einstein's Photoelectric Equation |
Â 83%
From NCERT
NEET - 2022
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The work functions of Caesium $$(\mathrm{Cs})$$, Potassium $$(\mathrm{K})$$ and Sodium $$(\mathrm{Na})$$ are $$2.14~\text{eV}$$, $$2.30~\text{eV}$$ and $$2.75~\text{eV}$$ respectively. If incident electromagnetic radiation has an incident energy of $$2.20~\text{eV}$$. which of these photosensitive surfaces may emit photoelectrons?
 1 $$\mathrm{Na}$$ only 2 $$\mathrm{Cs}$$ only 3 Both $$\mathrm{Na}$$ and $$\mathrm{K}$$ 4 $$\mathrm{K}$$ only
Subtopic: Â Photoelectric Effect: Experiment |
Â 65%
From NCERT
NEET - 2023