Answer:
(a)
(b) The force is repulsive
Explanation:
a) According to Coulomb's law, the magnitude of the electrice force that one particle exerts on the other is defined as:
Here k is the coulomb constant, and
are the signed magnitudes of the charges and d is the distance between them.
b) According to Coulomb's law, if the two charges have the same sign, the electrostatic force between them is repulsive.
Answer:
Its focal length is positive
Explanation:
A concave mirror is shown in attached figure. The distance from the pole to the focus of the mirror is called its focal length. Spherical mirrors are a part of a sphere.
As per conventions, we know that the axis opposite to x axis is taken as negative.
So, it is clear that the focal length of spherical concave mirror is negative.
Hence, the incorrect option is (c) " its focal length is positive".
