Advertisements
Advertisements
Question
Give the definition of intensity of light according to quantum concept and its unit.
Solution
Intensity of light refers to the strength or brightness or amount of light produced by a specific source. Its unit is the candela (cd).
APPEARS IN
RELATED QUESTIONS
Photons of wavelength λ are incident on a metal. The most energetic electrons ejected from the metal are bent into a circular arc of radius R by a perpendicular magnetic field having magnitude B. The work function of the metal is
How will you define threshold frequency?
Mention the two features of x-ray spectra, not explained by classical electromagnetic theory.
Briefly discuss the observations of Hertz, Hallwachs and Lenard.
Explain the effect of potential difference on photoelectric current.
List out the laws of photoelectric effect.
Give the applications photocell.
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.
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)
