PHYSICS [1 Mark Question Answer]

Refractive index of a medium with respect to vacuum is defined as the ratio of the speed of light in vacuum to the speed of light in the given medium.

Refractive index of a medium with respect to air is defined as the ratio of the speed of light in air to the speed of light in the given medium.

When light is allowed to pass through two prisms placed next to each other such that their adjacent faces are parallel, the first prism disperses the light into its seven colours and the second prism re-unites all the seven components of light and a ray of white light emerges out from the prism.

More the refractive index of a transparent medium, less is the speed of light passing through it.

No. a convex mirror always form an image smaller than the object.

The angle through which the incident ray is deviated by the prism is called the angle of deviation of the prism.

The angle between the emergent ray arid the normal is called angle of emergence.

It states that for a given pair of media of different densities, the ratio of the sine of angle of incidence to the sine of angle of refraction is always a constant.

Refractive index of a medium with respect to vacuum is defined as the ratio of the speed of light in vacuum to the speed of light in the given medium.

The angle between the refractec ray and the normal is called the angle of refraction.

The angle between the incident ray and the normal is called the angle of incidence.

The distance between the pole and the principal focus is called the focal length of the spherical mirror.

The straight line passing through the pole and the centre of curvature of the spherical mirror is called the principal axis.

The area of the mirror from which reflection takes place is called its aperture.

The geometrical centre of the spherical mirror is called the pole of the mirror.

The geometrical centre of the hollow sphere of which the spherical mirror is a part is called its centre of curvature.

The coin immersed in water appears to be raised due to refraction of light at the surface separating air and water.

Stars appear to twinkle due to the refraction of light coming from the star from different layers of the earth’s atmosphere.

Convex mirrors are preferred over plane mirrors as rear view mirrors in cars because convex mirrors always form an erect and diminished image, which gives a wider view of the vehicles coming behind.

Concave mirrors are used by dentists to see enlarged image of tooth and other area in mouth because concave mirrors produce virtual and magnified images of close objects. .

In a concave mirror, all rays of light parallel to the principal axis converge after reflection and meet at the principal focus. Due to this property, concave mirrors are also known as converging mirrors.

Objects waver on a really hot day due to the refraction of light by the different layers of the atmosphere.

A paper catches fire if a concave mirror is used to focus sunlight because concave mirror converges the parallel beam of light from the sun onto the paper. The large amount of heat getting concentrated on the paper raises its temperature, causing it to bum.