Chem problem- frequency of light given wavelength?

Question

How do you calculate the frequency of light when you're given the wavelength but not the speed? I know the equation for frequency is speed divided by wavelength, so I don't see how to do it without the speed part :P

Any help earns my undying love, I'm getting desperate. :D

NO WAY. Dude. Dumb fuh-reaking moment.
Thanks for not being like 'stfudumbperson'
Have a best answer award. :D

Answer 1

The speed is always the same! It's the speed of light, a constant so you can always work out the frequency if you are given the wavelength.

Answer 2

A useful property of light is that you ALWAYS know its speed. The speed of light is a universal constant, called "c".
c = 3.00*10^8 m/s

That should enable you to use the speed-frequency-wavelength equation more successfully.

Answer 3

Photoelectric effect. By the way, this is what Einstein got his Nobel prize for sorting out. They never gave him one for relativity. Conservation of energy. Energy of light photon = threshold energy + k.e. of the electron (1) To find the energy of the light photon used, and of the threshold energy, use E = Planck's constant x frequency You know the threshold frequency. You still need to find the frequency of the light used, and you can get this from frequency x wavelength = speed of wave = c You can now use Eq. (1) to calculate k.e. I expect you know the formula for kinetic energy: k.e.= 1/2m v^2 Where in this case m is the mass of the electron and v is the speed you want to find. Care with units; since k.e. is in J, and v is in m s-1, m has to be in kg. Good luck!

Answer 4

speed of light is ALWAYS "[3.0 x 10^8 m/s]"

so if they give you wavelength.. you just take 3.0x10^8 and divide it by the wavelength..... you will get frequency