Advertisements
Advertisements
Question
List out the characteristics of photons.
Advertisements
Solution
Characteristics of photons: According to the particle nature of light, photons are the basic constituents of any radiation and possess the following characteristic properties:
- The photons of light of frequency v and wavelength λ will have energy, given by
E = hv = `"hc"/λ` - The energy of a photon is determined by the frequency of the radiation and not by its intensity and the intensity has no relation with the energy of the individual photons in the beam.
- The photons travel with the velocity of light and its momentum is given by
p = `"h"/λ = "hv"/"c"` - Since photons are electrically neutral, they are unaffected by electric and magnetic fields.
- When a photon interacts with matter (photon-electron collision), the total energy, total linear momentum, and angular momentum are conserved. Since photons may be absorbed or a new photon may be produced in such interactions, the number of photons may not be conserved.
APPEARS IN
RELATED QUESTIONS
Two radiations with photon energies 0.9 eV and 3.3 eV respectively are falling on a metallic surface successively. If the work function of the metal is 0.6 eV, then the ratio of maximum speeds of emitted electrons in the two cases will be
If the mean wavelength of light from sun is taken as 550 nm and its mean power as 3.8 × 1026 W, then the average number of photons received by the human eye per second from sunlight is of the order of
The work functions for metals A, B and C are 1.92 eV, 2.0 eV and 5.0 eV respectively. The metal/metals which will emit photoelectrons for a radiation of wavelength 4100Å is/are
How does photocurrent vary with the intensity of the incident light?
Mention the different types of photocells.
Explain the effect of potential difference on photoelectric current.
Explain the quantum concept of light.
How many photons per second emanate from a 50 mW laser of 640 nm?
A 3310 Å photon liberates an electron from a material with energy 3 × 10−19 J while another 5000 Å photon ejects an electron with energy 0.972 × 10−19 J from the same material. Determine the value of Planck’s constant and the threshold wavelength of the material.
At the given point of time, the earth receives energy from the sun at 4 cal cm–2 min–1. Determine the number of photons received on the surface of the Earth per cm2 per minute. (Given: Mean wavelength of sunlight = 5500 Å)
