Wavelength And Frequency Test Paper

Wavelength (l) and Frequency (n) Relationships

c=ln ,

where l is wavelength in meters

n is frequency in hertz, 1/s or s-1

c=3.0 x 108m/s (the speed of light in a vacuum)

Typical question #1- What is the frequency of red light with a wavelength of 690.nm? (1m=109nm)

First- l is wavelength in meters, so convert nm to meters

690.nm (

1m )=6.90 x 10-7m

109nm

Now we can rearrange the equation above and solve for frequency, since we already know the constant, c.

n=c/l

n=

3.0 x 108m/s =4.35 x 1014 s-1

6.90 x 10-7m

Typical question #2- What is the wavelength of light in nm, that has a frequency of 6.6 x 1014 Hz?

l=c/n

l=

3.0 x 108m/s =4.55 x 10-7m
To calculate energy from frequency (or vice Versa), use the following equation

E=hn

where E is Energy in Joules (J)

n is frequency in hertz, 1/s or s-1

h=6.626 x 10-34 J s

Typical Question #1- How much energy does a photon of light with a frequency of 4.60 x 1014 s-1