It’s a force which acts on an object without coming physically in contract with it.
The answer to life is how ever you make it...... you can do anything with life that you would like.................. But make your choices worth it......
Answer:

Given:
Radius of curvature (R) of a spherical mirror = 20
To Find:
Focal length (f)
Explanation:
Formula:

Substituting value of R in the equation:



Answer:
are able to see/observe
Explanation:
Humans are not able to see most wavelengths in the universe--but there is a select range that is visible to our eyes. This (which is usually shown on an electromagnetic spectrum diagram/chart/depiction by a small portion of rainbow) is the visible light spectrum