energy equation given in terms of frequency

Question

Solve the energy equation given in terms of frequency: E = hc/λ. 

Answer 1

Since speed is distance/time, and c is the speed of light, we know that c = λ*f

(λ "wavelength" is a distance and f "frequency" is 1/time)

Solving for f: f = c/λ

Substitute f in the energy equation: E = h*c/λ = h*f

Solve this for f: E = h*f

f = E/h