A laser light travels at the speed of light, #300,000# #kms^-1#, and has a wavelength of #580# #nm#. What is its frequency?

1 Answer
Oct 24, 2017

The frequency of this light is #f=5.17xx10^14# #s^-1# (or #Hz#)

Explanation:

First we need to change the units into SI units: metres and metres per second:

#580# #nm# = #5.80xx10^-7# #m#
#300,000# #kms^-1# = #3.00xx10^8# #ms^-1#

The general equation for waves is:

#v=flambda#

We can rearrange this to make the frequency the subject:

#f=v/lambda=(3.00xx10^8)/(5.80xx10^-7)=5.17xx10^14# #s^-1# (or #Hz#)