Light of intensity and frequency falls normally on a photo-cathode of area

PHYSICS · Single correct · A Level · Physics · Particles and radiation · Particles and radiation

Problem

Light of intensity

0.5\,\text{W m}^{-2}

and frequency

5.0\times10^{14}\,\text{Hz}

falls normally on a photo-cathode of area

2.0\,\text{cm}^{2}

. If the quantum efficiency is

25\%

, estimate the saturation current. (Use

h = 6.63\times10^{-34}\,\text{J s}

e = 1.6\times10^{-19}\,\text{C}

.) (a)

6.0\,\mu\text{A}

(b)

48\,\mu\text{A}

(c)

12\,\mu\text{A}

(d)

3.0\,\mu\text{A}