Question

How do you calculate the wavelength of a helium-neon laser that says 95mW on it?

I have already done a diffraction grating but would like to double check that my results are accurate. I thought that calculating the wavelength of the laser I had used would give me more marks. Is it even possible to calculate the wavelength like this?
Thanks

Answer 1

All He-Ne lasers emit light at the same frequency. It isn't affected by power.

Explanation:

632.8 nm is the normally quoted wavelength, giving a frequency of 4.74 x `10^14` Hz.

The best way to measure the wavelength and hence find the frequency is by measuring diffraction patterns as you did. Most students can get within 1 or 2% with reasonable technique.