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

the force required to move the cart is divided by three or 33.33 n.

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