Question

the mass of a photon with wavelength 1A is

Answer 1

E=mc^2

E=hc/wavelength

So mc^2=hc/wavelength

mc=h/wavelength

m=hc/wavelength=12400/1 =12400 kg

(After putting the value of h and c we get 12400)

Answer 2

heya mate here is your answer
the
mass of photon is measured by following formula
If you take Einstein's equation E = m c^2 , where m = mass and c = speed of light, and the Planck equationfor the energy of a photon, E = h f , where h = Planck's constant and f = the frequency of the photon, and combine them you get: m c^2 = hf or that m = h f/c^2.