In a photoelectric experiment, with light of wavelength `lambda`, the fastest election has speed v. If the exciting wavelength is changed to `(3lambda)/4`, the speed of the fastest emitted electron will become

Options

A. ` = v(4/3)^(1/2)`
B. `=v (3/4)^(1/2)`
C. ` gt v (4/3)^(1/2)`
D. `lt v (4/3)^(1/2)`

Answer

C

Explanation

`hv_0^2 - hv_0 - 1/2 mv^2 therefore 4/3 hv_0 - hv_0 - 1/2 mv.^2`
` therefore (v.^2)/(v^2) = (4/3 v - v_0)/(v - v_0) therefore v. = v sqrt( (4/3 v - v_0)/(v - v_0) ) rArr v. gt v sqrt(4/3)`