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A photelectric meterial having work-func...

A photelectric meterial having work-function `phi_(0)` is illuminated with light of wavelegth `lamda(lamdalt(hc)/(4_(0))).` The fastes photoelectron has a de Broglie wevelength `lamda_(d).` A change in wavelength of the incident light by `Deltalamda` results in a change `Deltalamda_(d)` in `lamda_(d).` Then the ration `Deltalamda_(d)//Deltalamda` is proportional to

A

`(lambda_(d)^(3))/(lambda^(2))`

B

`(lambda_(d)^(3))/lambda`

C

`(lambda_(d)^(2))/(lambda^(2))`

D

`(lambda_(d))/lambda`

Text Solution

Verified by Experts

The correct Answer is:
A

`(hc)/lambda =W_(0)+KE_(max)`
`KE =(P^(2))/(2m_(e))=(h^(2))/(2m_(e)lambda_(d)^(2))`
`(hc)/lambda =phi_(0)+(h^(2))/(2m_(e)lambda_(d)^(2))`
`-(hc)/(lambda^(2))dlambda=0+(h^(2))/(2m_(e))((-2))/(lambda_(d)^(3))dlambda_(d)`
`(dlambda_(d))/(dlambda)=(m_(e)lambda_(d)^(3))/(h^(2)xxlambda^(2))hc`
`(dlambda_(d))/(dlambda)prop (lambda_(d)^(3))/(lambda^(2))` .
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