Question

An electromagnetic wave of wavelength '`lambda`' is incident on a photosensitive surface of negligible work function. If the photoelectrons emitted from this surface have the de-Broglie wavelength '`lambda_1`' then ____________.

Options

• `lambda prop lambda_1`

• `lambda prop 1/lambda_1^2`

• `lambda prop lambda_1^2`

• `lambda prop 1/lambda_1`

Answer 1

An electromagnetic wave of wavelength '`lambda`' is incident on a photosensitive surface of negligible work function. If the photoelectrons emitted from this surface have the de-Broglie wavelength '`lambda_1`' then `lambda prop lambda_1^2`.

Explanation:

`1/2 "mV"^2 = "hc"/lambda`

`therefore "p"^2/(2"m") = "hc"/lambda`

`therefore "p"^2 prop 1/lambda`

`"p" = "h"/lambda_1`

`therefore "h"^2/lambda_1^2 prop 1/lambda`

`therefore lambda prop lambda_1^2`