Question

the threshold wavelength foreign metal with work function w is Lambda what is the threshold wavelength for a metal whose work function is w by 2 ?​

Answer 1

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Answer 2

Threshold wavelength for a metal having work function is w by 2 is 2λ0.

A metal's work function,is the minimum amount of energy required to get a photon ejected. It's usually expressed electron volts or joules.

Threshold wavelength with work function w = λ

The work function of a metal is represented as-  

W = hv = hc/λ0

where, λ0 is the total threshold wavelength.

or W0 ∝ 1λ0

Hence, W0/W′0 =λ′0/ λ0

= W0/(W0/2)=λ′0/λ0

= λ′0 = 2λ0

Thus, the threshold wavelength is 2λ0.