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What is the maximum kinetic energy of electrons emitted form a surface of work function 3.2  eV when incident radiation of wavelength 300 nm falls on it.

What is the maximum kinetic energy of electrons emitted form a surface of work function 3.2  eV when incident radiation of wavelength 300 nm falls on it. Correct Answer <span class="math-tex">\(1.5 \times 10^{-19}\;J\)</span>

Given,

Work function = ω = 3.2 eV = 3.2 × 1.6 × 10-19 = 5.12 × 10-19 J

Wavelength = l = 300 nm = 3 × 10-7 m 

So, Frequency = ν = c / λ = 3 × 108 / 3 × 10-7 = 1015 Hz

Now,

\(hν=\omega+\frac{1}{2}{mv_{max}}^2\)

\(\\ or, \; K.E= \frac{1}{2}{mv_{max}}^2=hν-\omega\)

\(=6.62\times 10^{-34}\times 10^{15}-5.12\times 10^{-19}=1.5 \times 10^{-19}\;J\)

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