Question
Write Einstein’s photoelectric equation. State clearly the three salient features observed in photoelectric effect, which can be explained on the basis of the above equation.
✓
Answer
Einstein’s photoelectric equation:
$\text{K}_{max} = \text{hv} - \phi_{0} = \text{h}(\text{v} - \text{v}_{0})$
$\text{K}_{max} = \text{hv} - \phi_{0} = \text{h}(\text{v} - \text{v}_{0})$
- Kmax of electrons depends linearly on v.
- Kmax is independent of intensity of radiation.
- There exists a threshold frequency $\text{v}_{0}\it{( = \phi_{0}/\text{h})}$ for the metal surface, below which no photoelectric emission is possible. (No matter how intense the incident radiation may be or how long it falls on the surface.)
- For v > v0, photoelectric current is proportional to intensity of incident radiations.
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