Frequency is:
O
A. the distance between the top or bottom of a wave and the center
of the wave.
O
B. the noise floor acceptable in recording.
O
C. the number of waves in a certain amount of time.
O
D. the distance between two identical points on a wave.

Currents: NOAA's National Ocean Service Education. The highest surface part of a wave is called the crest, and the lowest part is the trough. The vertical distance between the crest and the trough is the wave height. The horizontal distance between two adjacent crests or troughs is known as the wavelength.

Explanation:

changeable lenses of different focal lengths allow light to enter the camera, which then forms the image on light-sensitive film" is the one among the following statements about working principle behind a basic still camera is true.