What is the wavelength (angstroms) of a photon that has an energy of 4.38 x 10-18 j?

The relationship between energy and frequency of a photon is given by E = h*f.

E is the energy, h is planck constant and f is the frequency and f= c/λ.

But i want wavelength, so i write this equation as E= h*c/λ.

now

c=3.8

E =4.38*  

where i replaced joules for  

h = 6.62607004 *

then λ = h*c/E =   = 5.7*  m

But you want the solution in angstroms, so 1  meter is angstroms

so λ  = 5.7*  = 570 angstrom

i don't understand. explain it clearly

you'd use the equation that establishes a relationship between  energy  and  wavelength, which looks like this

e=h⋅cλ, where

λ  - the wavelength of the photon; c  - the speed of light, usually given as  3⋅108m/s; h  -  planck's constant, equal to  6.626⋅10−34j s

plug the value you were given for the energy of the photon in the above equation to get the wavelength

e=h⋅cλ⇒λ=h⋅ce

λ=6.626⋅10−34js⋅3⋅108ms−1.257⋅10−24j=1.581⋅10−1m