# When monochromatic radiation of intensity I falls on a metal surface, the number of photoelectrons and their maximum kinetic energy are N and T respectively. If the intensity of radiation is 2I what is the number of emitted electrons and their maximum kinetic energy? 1. N and 2T 2. 2N and T 3. 2N and 2T 4. N and T

Subtopic:  Photoelectric Effect: Experiment |
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NEET - 2010
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A helium-neon laser produces monochromatic light of a wavelength of 667 nm. The power emitted is 9 mW. The average number of photons arriving per second on average at a target irradiated by this beam is:

1. $9×{10}^{17}$

2. $3×{10}^{16}$

3. $9×{10}^{15}$

4. $3×{10}^{19}$

Subtopic:  Particle Nature of Light |
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NEET - 2009
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Waves are associated with matter only:

 1 When it is stationary. 2 When it is in motion with the velocity of light only. 3 When it is in motion with any velocity. 4 None of the above.

Subtopic:  De-broglie Wavelength |
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From NCERT
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A particle which has zero rest mass and non-zero energy and momentum must travel with a speed:

 1 Equal to c, the speed of light in vacuum. 2 Greater than c. 3 Less than c. 4 Tending to infinity.

Subtopic:  De-broglie Wavelength |
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If the following particles are moving at the same velocity, then which among them will have the maximum de-Broglie wavelength?
1. Neutron

2. Proton

3. $\mathrm{\beta }$-particle

4. $\mathrm{\alpha }$-particle

Subtopic:  De-broglie Wavelength |
59%
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What is the momentum of a photon in an X-ray beam of 10-10 meter wavelength?

 1 $$1.5 \times 10^{-23} \mathrm{~kg}-\mathrm{m} / \mathrm{sec}$$ 2 $$6.6 \times 10^{-24} \mathrm{~kg}-\mathrm{m} / \mathrm{sec}$$ 3 $$6.6 \times 10^{-44} \mathrm{~kg}-\mathrm{m} / \mathrm{sec}$$ 4 $$2.2 \times 10^{-52} \mathrm{~kg}-\mathrm{m} / \mathrm{sec}$$

Subtopic:  De-broglie Wavelength |
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The energy of a quanta of frequency ${10}^{15}$ Hz and  will be:

1. $6.6×{10}^{-19}$ $\mathrm{J}$

$\mathrm{}$2.$6.6×{10}^{-12}$ $\mathrm{J}$

3. $6.6×{10}^{-49}$ $\mathrm{J}$

$\mathrm{}$4.$6.6×{10}^{-41}$ $\mathrm{J}$

Subtopic:  Particle Nature of Light |
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The number of photo-electrons emitted per second from a metal surface increases when:

 1 The energy of incident photons increases. 2 The frequency of incident light increases. 3 The wavelength of the incident light increases. 4 The intensity of the incident light increases.
Subtopic:  Photoelectric Effect: Experiment |
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A photon of energy 3.4 eV is incident on a metal having a work function of 2 eV. The maximum K.E. of photo-electrons is equal to:

 1 1.4 eV 2 1.7 eV 3 5.4 eV 4 6.8 eV
Subtopic:  Einstein's Photoelectric Equation |
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A photocell is receiving light from a source placed at a distance of 1 m. If the same source is placed at a distance of 2 m, then the ejected electron:

 1 moves with one-fourth of energy as that of the initial energy. 2 moves with one-fourth of momentum as that of the initial momentum. 3 will be half in number. 4 will be one-fourth in number.
Subtopic:  Electron Emission |
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