Find the threshold wavelengths for photoelectric effect from a copper surface, a sodium surface and a cesium surface. The work functions of these metals are 4.5 eV, 2.3 eV and 1.9 eV respectively.

Explanation

To find the threshold wavelengths for the photoelectric effect from copper, sodium, and cesium surfaces, we will use the formula:

\[ \lambda_0 = \frac{hc}{\phi} \]

where:
- \(\lambda_0\) is the threshold wavelength,
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