Correct Answer - Option 1 :
6.626 × 10-27 Kg-m/s
CONCEPT:
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Photon: The photon is an elementary particle. It is a basic unit of light.
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Photons are massless, and they always move at the speed of light in a vacuum ( c = 3 × 108 m/s)
- The momentum of a photon: It is given by Planck's constant divided by the wavelength of the light.
\(P=\frac{h}{λ}\)
where P is the momentum of one photon, h is the Planck constant, and λ is the photon's wavelength. In this equation h is constants.
CALCULATION:
Given that: λ = 1000 Å = 1000 × 10-10 m
h = 6.626 × 10-34 (constant)
c = 3 × 108 (constant)
p = h / λ
⇒ p = 6.626 × 10-34 / 1000 × 10-10
⇒ p = 6.626 × 10-27 Kg-m/s
The correct answer is Option 1 i.e 6.626 × 10-27 Kg-m/s
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Despite photons having no mass, Photon particles carry momentum as well as energy.
- There has been evidence that EM radiation carries momentum. (Maxwell and others who studied electromagnetic waves have predicted that these carry momentum.)
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It is now a well-established fact that photons do have momentum and energy.
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Photon energy is the energy that is carried by a single photon. The amount of this energy is inversely proportional to the wavelength.