# Calculating Frequencies using Wavelength

I know frequency=1/time period, so I can calculate frequency from time period, but how do you calculate it from only just wavelength?
You should know that v = fλ, where v is the speed of the wave (in m s^-1), f is the frequency (in Hz or s^-1) and λ is the wavelength (in m).

It therefore follows that v/λ = f

For an electromagnetic wave, v = the speed of light, which is 299,792,458 m s^-1 (call it 3 x 10^8 at A level).
Original post by TypicalNerd
You should know that v = fλ, where v is the speed of the wave (in m s^-1), f is the frequency (in Hz or s^-1) and λ is the wavelength (in m).

It therefore follows that v/λ = f

For an electromagnetic wave, v = the speed of light, which is 299,792,458 m s^-1 (call it 3 x 10^8 at A level).

is v always the speed of light?
Only for electromagnetic waves
Original post by TypicalNerd
Only for electromagnetic waves

If not, you should be given it in the question
Original post by TypicalNerd
Only for electromagnetic waves

ok, that's lucky.
I was supposed to calculate frequency of X-Rays using the wavelength

Original post by TypicalNerd
If not, you should be given it in the question

thanks!