The fig. shows the variation of photon current with anode potential for a photo-sensitive surface for three different radiation. Let `I_(a), I_(b) and I_(c)` be the intensities and `f_(a), f_(b) and f_(c)` be the frequency for the curves a,b and c respectively.

Options

A. `f_(a) = f_(b), l_(a) != l_(b)`
B. `f_(a) = f_(c ), l_(a) = l_(c )`
C. `f_(a) = f_(b), l_(a) = l_(b)`
D. `f_(b) = f_(c), l_(b) = l_(c )`

Answer

A

Explanation

stopping potential for a and b are same. Hence `f_(a)=f_(b)` but current `l_(b)` is more than `l_(r )` at zero potential