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Find the maximum wavelength of light tha...

Find the maximum wavelength of light that can cause photoelectric effect in lithium.

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the work functions of lithium is
2.5 eV. The threshold wavelength is
` lambda = hc/varphi .`
`= ((4.14 xx (10^-15)eVs) xx ( 3 xx (10^8)m(s^-1))/ 2.5eV)`
` (1242 e V nm / 2.5 eV) = 497 nm.`
This is the required maximum wavelength.
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