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A surface is irradiated with ultraviolet...

A surface is irradiated with ultraviolet radiation of wavelength `0.2 mum`. If the maximum velocity of electron liberated from the surface is `8.8 xx 10^(5)m//s`, then find the work function of the surface.

A

3 eV

B

4 eV

C

5 eV

D

6 eV

Text Solution

Verified by Experts

The correct Answer is:
D
We know that E = hv = `(hc)/(lambda)`
`E=(6.6xx10^(-34)xx3xx10^(8))/(0.2 xx10^(-6))`
`=(1.98xx10^(-25))/(0.2 xx10^(-6))=9.9xx10^(-19)J`
Also, `" "E-W_(0)=(1)/(2)mv^(2)`
`9.9xx10^(-19)-W_(0)=(1)/(2)xx9.1xx10^(-31)(8.8xx10^(5))^(2)`
`W_(0)=9.9xx10^(-19)-3.52xx10^(-19)`
`W_(0)=6.38~~ 6 eV`
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