Advertisements
Advertisements
प्रश्न
Define the work function of a metal. Give its unit.
Advertisements
उत्तर
The minimum energy needed for an electron to escape from the metal surface is called the work function of that metal. Its unit is electron volt (eV).
APPEARS IN
संबंधित प्रश्न
The work function of caesium metal is 2.14 eV. When light of frequency 6 × 1014 Hz is incident on the metal surface, photoemission of electrons occurs. What is the
- maximum kinetic energy of the emitted electrons,
- Stopping potential, and
- maximum speed of the emitted photoelectrons?
Quarks inside protons and neutrons are thought to carry fractional charges [(+2/3)e; (–1/3)e]. Why do they not show up in Millikan’s oil-drop experiment?
How does one explain the emission of electrons from a photosensitive surface with the help of Einstein's photoelectric equation?
How will the thermionic current vary if the filament current is increased?
Why does thermionic emission not take place in non-conductors?
The work function of aluminum is 4⋅2 eV. If two photons each of energy 2⋅5 eV are incident on its surface, will the emission of electrons take place? Justify your answer.
The wavelength λe of an electron and λp of a photon of same energy E are related by ______.
What do you mean by electron emission? Explain briefly various methods of electron emission.
A 150 W lamp emits light of the mean wavelength of 5500 Å. If the efficiency is 12%, find out the number of photons emitted by the lamp in one second.
Give an example each of a metal from which photoelectric emission takes place when irradiated by
- UV light
- visible light.
