Is there a certain context to this question so that I can answer it better?
False. That description fits the wave's 'frequency'.
It has nothing to do with refraction.
Answer:
the focal length is 4cm
Explanation:
use the formula 1+1/m = f
it is obtained from the mirror formula
m is the magnification and is the ratio of the image height to the object height
however they should have the same unit . that means you would have to do a little conversion from cm to mm or vice versa .
Stars are located at a distance which are measured in terms of light years. Light year is an Astronomical unit used to measure distance between distant Celestial bodies.
1 light year = 9460730472580<span>800 metres
But no star is located at a distance of 1 light year. Some stars are located at millions of light years and light travels ~ 3 x 10</span>⁸ m/s. Thus light takes time to reach our atmosphere.
Space ships.
Hope this helps and have a nice day!!!