Physics

Define the main axis of a mirror? The straight line across the pole and the center of curvature of a mirror is known as the main axis of a mirror.

What is the center of curvature? The center of the sphere of which the mirror is a part, is known as the center of curvature.

What is the main focus of a spherical mirror? After reflection, if light rays parallel to the main axis of a spherical mirror joins a point (convex mirror) or seems to converge from a point (concave mirror), then that point is known as the main focus of a spherical mirror.

What do you mean by a coating of silver? To make a mirror, one surface of the glass mirror is coated with mercury or silver. This process is known as silvering.

What do you mean by real image? If some light rays emitted from a point get reflected or refracted in a plane and if they meet in a second point, then that 2nd point is known as the real image of the first point.

Explain fluid friction. When an object moves in a fluid, i.e. a liquid or gas, the friction acts is called fluid friction. We have to overcome a barrier in water while swimming in the pond. This barrier is the fluid friction. A parachute works by harnessing the air resistance. The air resistance is a type … Read more

What is unbalanced force? When two or more forces acting on an object produce resultant force, i.e. the object has acceleration; we say that the forces are unbalanced. The forces that produce this unbalanced condition are called unbalanced forces.

Explain the firing by a gun. When a person fires with a gun, he feels a backward push at that time. In this case, action and reaction force of bullet and gun exists for the same time. According to Newton’s second law of motion, the bullet and the gun acquire equal and opposite momentum. As … Read more