Question

________ is the friction which comes into play when surfaces of the objects are at rest relative to each other even there is an external force acted upon​

Answer 1

Explanation:

Mirrors, whose reflecting surfaces are curved and can be imagined as part of a sphere, are called spherical mirrors. If the reflecting surface of a spherical mirror is curved outwards, it is called a convex mirror. Whereas a mirror with a reflecting surface, which is bent inwards, is called a concave mirror. Concave mirrors reflect and focus incoming light rays (parallel) at a point, called the focus point. Depending on the distance of an object from the reflecting surface, different types of images are formed. Both kinds of mirrors are used in science and technology. These are used in daily life also. Concave mirrors are used as headlights, torches, head mirrors, solar furnaces, microscopes, telescopes, etc.