Question

1A light source of power 50watt emitting a light of wavelength 5000A° which incident on a surface normally the surface behaviour as 50% perfectly reflecting surface find the force exerted on the surface
1) 25×10-6n 2) 25×10-9n
3) 15×10-8n 4) 25×10-8n

Answer 1

option 3....................

Answer 2

hope this helps you

use E = nhv

and power is E/t.

u will get as P = ( n.h.v)/t.

get n/t .

later by multiplying it by electrons. this will become this much electron gives current.(only photo electron)

here I used n for photon as well as photo electrons because x no of photons will eject same no photoelectrons provided energy of photon is greater than workfunction of surface.