Question

What is the wavelength of a photon that has an energy of `4.41 x 10^-19`?

Answer 1

What unit of energy are you using? I assume it's J...? In which case its about 4.5 x `10^-7` m

Explanation:

If you use Planck-Einstein equation, E = h.f where h is Planck's constant, which 6.626 x `10^-34` J.s, then you can work out the frequency: f = E/h, = 4.41 x `10^-19`/6.626 x `10^-34` = 6.655 x `10^14` Hz.

Then convert frequency to wavelength using `lambda` = c/f where c is the speed of light, 3 x `10^8` m/sec.

`lambda` = 3 x `10^8` / 6.655 x `10^14` = 4.51 x `10^-7` m.