PHYSICS [1 Mark Question Answer]

Given:Speed of light in medium (v₂) = 0.75 × 10⁸ m/s,
velocity of light in vacuum (v₁) = 3 × 10⁸ m/s
To find:Absolute refractive index (n)
Formula: n = v¹/v²
Calculation: From the formula,
n = 3 × 10⁸ m/s/0.75 × 10⁸ m/s
n = 4
The absolute refractive index of the medium is 4

Refractive index, also called index of refraction, measure of the bending of a ray of light when passing from one medium into another.

When light Ray travels from denser to rarer medium it shifts away from normal and angle of incidence is greater than that of refraction

When a light Ray travels from rarer to denser medium. It shifts toward normal and angle of refraction is smaller than that of angle of incidence.

Laws of refraction state that: The incident ray refracted ray, and the normal to the interface of two media at the point of incidence all lie on the same plane. The ratio of the sine of the angle of incidence to the sine of the angle of refraction is constant. This is also known as Snell’s law of refraction.
Examples of refraction of light:
Twinkling of stars in a clear sky.
Pool of water appears to be less deep than it actually is.
Rainbow formation in the sky.

Angle between the refracted ray and the normal.

Angle between the incident ray and the normal.

An emergent ray seems to be a refracted beam that originates from a medium or channel after refraction.

Imaginary straight line perpendicular to the refracting surface at the point of refraction.

Refracted rays can be defined as the part of rays that moves after deviation in the medium after ray incident on its boundary from a another medium.

An incident ray is a rectilinear ray of light that strikes a surface, known as incident ray on that spot(surface). The angle between this ray and the perpendicular or normal to the surface is the angle of incidence.

This is because of refraction of light. As light passes from water to air, it bends away from the normal. The refracted rays appear to come from a point above the actual position of the coin, hence the coin appears raised.

The bending of a ray of light obliquely on a surface when it passes from one medium to another is called refraction.

During refraction through a glass block, with the increase in angle of incidence, the angle of refraction increases.

When a ray of light travels from an optically less denser medium to an optically more denser medium, the angle of incidence is always more than angle of refraction.

The ratio between the velocity of light in a vacuum to the velocity of light in media is called refractive index.

A ray of light is incident perpendicularly on a glass slab. The angle of incidence is 0°

When a ray of light travels from optically denser medium to optically rarer medium, it always bends away the normal.