Question

The frequency of a wave does not change as
the wave moves from one material to another.
Find the wavelength of this wave in vacuum.
Answer in units of m
Frequency 1.2698*10^14
I got .000002 but it was wrong.

Answer 1

Perhaps you need more decimal places? We typically give wavelengths with 3 or 4 significant digits. Your answer appears to be approximately correct. Double check to be sure you used the right units. The equation used should be:\[c=\lambda \nu \]where c is the speed of light; λ is the wavelength; and ν is the frequency.

By my calculation:\[\lambda=2.361*10^{-6}m=2.361\mu m\]assuming that the frequency was given in Hz. For the record, that's a wavelength in the infrared spectrum.

Answer 2

Note that a few digits can make a big difference when it comes to wavelength and frequency. For instance a wavelength given as only 7*10^-9m could be 6.50*10^-9m or 7.49*10^-9m, with the former being in the visible spectrum and the latter being in the infrared and undetectable to most people's eyes.