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Two metals A and B have work functions 4...

Two metals A and B have work functions 4 eV and 10 eV respectively. Which metal has higher threshold wavelength?

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Work function, `phi_0=(hc)/(lambda_0)`, where `lambda_0` is the threshold wavelength. So, `lambda_0 prop 1//phi_0`. It means a metal with lower work function has higher threshold wavelength.
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