Advertisements
Advertisements
Question
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
Solution
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
RELATED QUESTIONS
Find the maximum frequency of X-rays produced by 30 kV electrons.
Why does thermionic emission not take place in non-conductors?
The anode of a thermionic diode is connected to the negative terminal of a battery and the cathode to its positive terminal.
The constant A in the Richardson−Dushman equation for tungsten is 60 × 104 A m−2K−2. The work function of tungsten is 4.5 eV. A tungsten cathode with a surface area 2.0 × 10−5 m2 is heated by a 24 W electric heater. In steady state, the heat radiated by the heater and the cathode equals the energy input by the heater and the temperature becomes constant. Assuming that the cathode radiates like a blackbody, calculate the saturation current due to thermions. Take Stefan's Constant = 6 × 10−8 W m−2 K−1. Assume that the thermions take only a small fraction of the heat supplied.
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
If a light of wavelength 330 nm is incident on a metal with work function 3.55 eV, the electrons are emitted. Then the wavelength of the wave associated with the emitted electron is (Take h = 6.6 × 10–34 Js)
What do you mean by electron emission? Explain briefly various methods of electron emission.
In which case is electron emission from a metal not known?
Photoelectric emission is observed from a metallic surface for frequencies ν1 and ν2 of the incident light (ν1 > ν2). If the maximum value of kinetic energy of the photoelectrons emitted in the two cases are in the ration 1 : n then the threshold frequency of the metallic surface is ______.
