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The threshold wavelength of Na element i...

The threshold wavelength of Na element is 6800 Å.Its work function is ……….`xx10^(-19)J.(h=6.625xx10^(-34)Js,C=3xx10^(8)ms^(-1))`

A

2.9

B

2.7

C

2.8

D

3

Text Solution

Verified by Experts

The correct Answer is:
A
`phi=hf_(0)=(hc)/(lambda_(0))`
`therefore phi=(hc)/(lambda_(0))=(6.625xx10^(-34)xx3xx10^(8))/(68xx10^(-8))`
`=0.2922xx10^(-18)=2.922xx10^(-19)J`
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