# An electron and a photon each have a wavelength of 1.00 nm. The momentum of the electron will be: 1. Greater than photon. 2. Equal to the photon. 3. Less than photon. 4. None of these.

Subtopic:  De-broglie Wavelength |
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The work function of cesium metal is $$2.14$$ eV. When light of frequency $$6\times10^{14}$$ Hz is incident on the metal surface, photoemission of electrons occurs. What is the stopping potential of the metal?
1. $$0.212$$ V
2. $$0.345$$ V
3. $$0.127$$ V
4. $$0.311$$ V

Subtopic:  Einstein's Photoelectric Equation |
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The photoelectric cut-off voltage in a certain experiment is $$1.5~\mathrm{V}$$. What is the maximum kinetic energy of photoelectrons emitted?
1. $$2.1 \times 10^{-19} \mathrm{~J}$$
2. $$1.7 \times 10^{-19} \mathrm{~J}$$
3. $$2.4 \times 10^{-19} \mathrm{~J}$$
4. $$1.1 \times 10^{-19}~\mathrm{J}$$

Subtopic:  Photoelectric Effect: Experiment |
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Monochromatic light of wavelength $$632.8~\text{nm}$$ is produced by a helium-neon laser. The power emitted is $$9.42~\text{mW}$$. The energy of each photon in the light beam is:
1. $$4.801 \times 10^{-19}~\text{J}$$
2. $$2.121 \times 10^{-19}~\text{J}$$
3. $$5.043 \times 10^{-19}~\text{J}$$
4. $$3.141 \times 10^{-19}~\text{J}$$

Subtopic:  Particle Nature of Light |
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The energy flux of sunlight reaching the surface of the earth is $$1.388\times10^{3}$$ W/m2. How many photons (nearly) per square meter are incident on the Earth per second? Assume an average wavelength of $$550~\text{nm}$$.
1. $$3.84\times10^{21}$$
2. $$2.97\times10^{21}$$
3. $$4.12\times10^{21}$$
4. $$2.10\times10^{21}$$

Subtopic:  Particle Nature of Light |
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In an experiment on the photoelectric effect, the slope of the cut-off voltage versus frequency of incident light is found to be . The value of Planck's constant is:

1.
2.
3.
4.

Subtopic:  Einstein's Photoelectric Equation |
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A $$100$$ W sodium lamp radiates energy uniformly in all directions. The lamp is located at the center of a large sphere that absorbs all the sodium light which is incident on it. The wavelength of sodium light is $$589$$ nm. What is the energy per photon associated with the sodium light?
1. $$1.21$$ eV
2. $$2.21$$ eV
3. $$2.11$$ eV
4. $$1.11$$ eV

Subtopic:  Particle Nature of Light |
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Light of frequency  is incident on a metal surface. Electrons with a maximum speed of  are ejected from the surface. What is the threshold frequency for the photoemission of electrons?

1. $$5.109 \times10^{14}$$ Hz
2. $$3.45 \times10^{14}$$ Hz
3. $$6.733 \times10^{14}$$ Hz
4. $$4.738 \times10^{14}$$ Hz

Subtopic:  Einstein's Photoelectric Equation |
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The threshold frequency for a certain metal is  If the light of frequency  is incident on the metal, the cut-off voltage for the photoelectric emission is:

1. 1.1210 V.
2. 2.0292 V.
3. 3.8651 V.
4. 4.0832 V.

Subtopic:  Einstein's Photoelectric Equation |
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Light of intensity 10-5 W m-2 falls on a sodium photo-cell of surface area 2 cm2. Assuming that the top 5 layers of sodium absorb the incident energy, The time required for photoelectric emission in the wave-picture of radiation is: (The work function for the metal is given to be about 2 eV.)

1. 0.2 year
2. 0.3 year
3. 0.4 year
4. 0.5 year

Subtopic:  Einstein's Photoelectric Equation |
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