Question

100W bulb emmit the light of 400nm calculate the no of photons emmited by the bulb per second

Answer 1

Here's the solution.

The formulas used are as follows:

E = h×f

where E is energy
h is Planck's Constant
f is frequency

Other equation used is
v=(lambda)×f

where v is velocity
And lambda is wavelength

As here we are talking about photons, which make up light, v=c=speed of light

Hope it helps