What is force? And tell it's unit

force is simply a push or a pull in a particular direction. The unit is N (newton)

Explanation:

hope this helped

In physics force is an influence which changes the motion of an object which has mass

Its unit is N or kgms/2

54 degrees incident angle = reflected angle

angle is from normal turned to line of ray

electric field is a function of 1/r^2

yes, the force per unit charge for a point charge is inverse square law.