What is the energy (in ev units) carried by one photon violet light that has a wavelength of 4.5e-7?

The energy of a photon is given by

where h is the Planck constant and f is the photon frequency.

We can find the photon's frequency by using the following relationship:

where c is the speed of light and  is the photon's wavelength. By plugging numbers into the equation, we find


And so now we can find the photon energy


We know that 1 Joule corresponds to

So we can convert the photon's energy into electronvolts:

Hahahahaha nice. my guess would be age or they moved the grocery store. ; ) and remind him next time you are late getting home that it takes a long time to go 12miles, hahahave a good one!