Find the (a) maximum kinetic energy of photoelectrons ejected from potassium surface, for which , `phi=2.1 eV`, by photons of wavelengths 2000 Å and 5000 Å. (b) What is the threshold frequency `v_(0)` and (c) the corresponding wavelength?

Explanation

To solve the problem step by step, we will use Einstein's photoelectric equation:

\[ KE_{\text{max}} = \frac{hc}{\lambda} - \phi \]

where:
- \( KE_{\text{max}} \) is the maximum kinetic energy of the emitted photoelectrons,
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