Question

Explain what is photoelectric effect..also gives its characters and the observations of photo electric effect made ..

Chemistry

Answer 1

Heya !
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★Photoelectric effect ★
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→ What is photoelectric effect ?

=> This effect deals with the ejection of electrons from the surface of a neutral gaseous atom .

=>This is done when light of a suitable frequency strikes the surface of metals .

=> The ejected electrons are called Photo Electrons.

=>Metals Like Cesium show maximum photoelectric effect .


→ Observations of Photo Electric Effect -
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↪Electrons are ejected from the surface of the metal as soon as light strikes on its surface .

↪For each metal , a light of minimum frequency is required to eject an electron . Thus frequency is called the Threshold Frequency .

↪The Kinetic Energy of the ejected electrons is directly proportional to the frequency of radiation.

↪The number of ejected electrons depends on the intensity of the radiation .

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Answer 2

The photoelectric effect is the emission of electrons or other free carriers when light shines on a material. Electrons emitted in this manner can be called photo electrons. According to classical electromagnetic theory, this effect can be attributed to the transfer of energy from the light to an electron.


Observations of Photoelectric Effect 

1. Existence of threshold frequency

For a given metal, no photoelectrons are emitted if the frequency of the incident light is lower than a certain frequency.

2. Emission is instantaneous

Emission of photoelectrons takes place almost instantaneously after the light shines on the metal, with no detectable time delay. 

3. Maximum Kinetic Energy of the photoelectron is independent of intensity of incident electromagnetic radiation

Photoelectrons emitted from a metal have a range of velocities from zero up to a maximum VmaxVmax. The maximum kinetic energy 12mV2max12mVmax2 was found to depend linearly on the frequency of the radiation and is independent of its intensity.