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

Answer

B

Explanation

By using `E = W_(0) + K_(max) = E - W_(0)`
Hence , `K_(1) = 1 - 0.5 = 0.5`
and `K_(2) = 2.5 - 0.5 = 2 rArr (K_(1))/(K_(2)) = (1)/(4)`.