Question

how do you find the wavelength of a wave with the frequency with joules or ergs

Answer 1

Now lets see a question according to you

What is the number of photons(take photons as wavelenght and apply the formula of wavelength) of light with a wavelength of 4000 pm that provide 1 J of energy?

The answer would be:

Energy (E) of a photon = hc/λ

Where,λ = wavelength of light = 4000 pm = 4000 ×10–12 m = 4x 10-9 m

c = velocity of light in vacuum = 3 × 108 m/s

h = Planck’s constant = 6.626 × 10–34 Js

thefore the energy of photon (E)

= 6.626 × 10–34 Js X 3 × 108 m/s / 4x 10-9 m = 4.965 x 10-16 J

Now 4.965 x 10-16 J is the energy of = 1 photon

Therefore 1 J will be the energy of = 1/4.965 x 10-16 J = 2.014 x 1015 photons

(TAKE THE PHOTON FORMULA AND CHANGE IT INTO WAVELENGTH FORMULA)

AND YOUR SUM IS DONE.