Advertisements
Advertisements
Question
Why do metals have a large number of free electrons?
Solution
In metals, the electrons in the outermost shells are loosely bound to the nucleus. Even at room temperature, there are a large number of free electrons which are moving inside the metal in a random manner.
APPEARS IN
RELATED QUESTIONS
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?
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 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.
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)
Emission of electrons by the absorption of heat energy is called ____________ 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.
