Advertisements
Advertisements
प्रश्न
Calculate the energies of the photons associated with the following radiation:
- violet light of 413 nm
- X-rays of 0.1 nm
- radio waves of 10 m
Advertisements
उत्तर
E = hv
E = `"hc"/λ` in Joule
E = `"hc"/(λe)` in eV
i. violet light of 413 nm
E = `(6.625 xx 10^-34 xx 3 xx 10^8)/(413 xx 10^-9 xx 1.6 xx 10^-19)`
= `19.875/660.8 xx 10^-26 xx 10^28`
= 0.032 × 102
E = 3 eV
ii. X-rays of 0.1 nm
E = `(6.625 xx 10^-34 xx 3 xx 10^8)/(0.1 xx 10^-9 xx 1.6 xx 10^-19)`
= `(19.875 xx 10^-26)/(0.16 xx 10^-28)`
= 124.24 × 102
E = 12424 eV
iii. radio waves of 10 m
E = `(6.625 xx 10^-34 xx 3 xx 10^8)/(10 xx 1.6 xx 10^-19)`
= `19.875/1.6 xx 10^-26 xx 10^-1 xx 10^19`
E = 1.24 × 10−7 eV
APPEARS IN
संबंधित प्रश्न
A photoelectric surface is illuminated successively by monochromatic light of wavelength λ and `λ/2`. If the maximum kinetic energy of the emitted photoelectrons in the second case is 3 times that in the first case, the work function of the material is
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
A light of wavelength 500 nm is incident on a sensitive metal plate of photoelectric work function 1.235 eV. The kinetic energy of the photoelectrons emitted is (Take h = 6.6 × 10–34 Js)
Obtain Einstein’s photoelectric equation with the necessary explanation.
Explain experimentally observed facts of the photoelectric effect with the help of Einstein’s explanation.
Calculate the maximum kinetic energy and maximum velocity of the photoelectrons emitted when the stopping potential is 81 V for the photoelectric emission experiment.
When a light of frequency 9 × 1014 Hz is incident on a metal surface, photoelectrons are emitted with a maximum speed of 8 × 105 ms−1. Determine the threshold frequency of the surface.
When a 6000 Å light falls on the cathode of a photo cell, photoemission takes place. If a potential of 0.8 V is required to stop emission of electron, then determine the
- frequency of the light
- energy of the incident photon
- work function of the cathode material
- threshold frequency and
- net energy of the electron after it leaves the surface.
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)
UV light of wavelength 1800 Å is incident on a lithium surface whose threshold wavelength is 4965 Å. Determine the maximum energy of the electron emitted.
