## Equations for Light Only

$E=hv$

Megan Wong 4E
Posts: 32
Joined: Thu Sep 27, 2018 11:28 pm

### Equations for Light Only

Which equations from this chapter can be used for light only and which (besides the kinetic energy equation) can be used for electrons only?

Sameen Mahmood 3D
Posts: 37
Joined: Wed Jun 13, 2018 2:00 am

### Re: Equations for Light Only

All of the equations are given on the test and you can use all of them for everything based on the conditions given. The only restriction is De Broglie because it only applies to things with rest mass.

Sophia Ding 1B
Posts: 47
Joined: Thu Sep 27, 2018 11:16 pm

### Re: Equations for Light Only

You can't use E = hv (or E = hc/wavelength for that matter) for electrons as that measures the energy for photons only. De Broglie's is what you would use to figure out wavelength for electrons given it's mass and velocity (sometimes you'll have to solve for velocity using the kinetic energy formula), but other than that I don't think there are major restrictions we need to know of.

Marwan Masri 3B
Posts: 31
Joined: Thu Sep 27, 2018 11:23 pm

### Re: Equations for Light Only

You could use E=hv and E=hc/wavelength for light, but de Broglie's equation only applies to particles (even though it was derived from equations for light).