Answer: wavelength !!
hope this helped :)
When I see the word "which" at the beginning of your question,
I just KNOW that there's a list of choices printed right there
next to he part that you copied, and for some mysterious
reason, you decided not to let us see the choices.
Any flashlight, light bulb, laser, or spark ... like lightning ...
converts some electrical energy into some light energy.
Higher pitched sounds produce waves which are closer together than for lower pitched sounds. A smaller triangle or cymbal will make a relatively higher pitch note
Answer:
Secrets? Cuz if I share you the secrets then the secrets will no longer will be secrets.