Advertisements
Advertisements
प्रश्न
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.
Advertisements
उत्तर
By using Einstein's photoelectric equation is, K. E. = hv - Φ or hv = Φ + K. E. we can say that the emission of electrons takes place only if the incident energy is greater than the work function of the material.
In the given case, total incident energy =2 × 2.5 eV = 5 eV
The work function of aluminum, Φ = 4.2 eV
∵ Incident energy is greater than the work function of the material, hence the emission of electrons will take place.
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?
How will the thermionic current vary if the filament current is increased?
Would you prefer a material with a high melting point or a low melting point to be used as a cathode in a diode?
Would you prefer a material with a high work-function or a low work-function to be used as a cathode in a diode?
An isolated metal sphere is heated to a high temperature. Will it become positively charged due to thermionic emission?
A diode value is connected to a battery and a load resistance. The filament is heated, so that a constant current is obtained in the circuit. As the cathode continuously emits electrons, does it become more and more positively charged?
Define the term "Threshold frequency", in the context of photoelectric emission.
The wave associated with a moving particle of mass 3 × 10–6 g has the same wavelength as an electron moving with a velocity 6 × 106 ms–1. The velocity of the particle is
Emission of electrons by the absorption of heat energy is called ____________ emission.
Define the work function of a metal. Give its unit.
