Lights of two different frequencies whose photons have energies 1 and 2.5 eV, respectively, successively illuminate a metal whose work function is 0.5 eV. The ratio of the maximum speeds of the emitted electrons

Options

A. `1:2`
B. `1:1`
C. `1:5`
D. `1:4`

Answer

A

Explanation

`v_("max")=sqrt((2)/(m)(KE_("max")))=sqrt((2)/(m)(E_(Ph)-W))`
`(v_(1))/(v_(2))=sqrt((1-0.5)/(2.5-0.5))=sqrt((0.5)/(2))=1:2`