Q46 / 60 · JEE Advanced 2014 (Paper 2) · Physics

A metal surface is illuminated by light of two different wavelengths 248 nm and 310 nm. The maximum speeds of the photoelectrons corresponding to these wavelengths are u₁ and u₂, respectively. If the ratio $u_{1} : u_{2} = 2 : 1$ , the work function of the metal is nearly

Correct answer
A
3.7 eV
B
3.2 eV
C
2.8 eV
D
2.5 eV

Solution

\frac{\frac{h c}{λ_{1}} - ϕ}{\frac{h c}{λ_{2}} - ϕ} = \frac{u_{1}^{2}}{u_{2}^{2}}

ϕ = 3.7 e V

Hence, the correct answer is option: 'A'.

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