Why total internal reflection Cannot take place from rarer to denser medium?

When light travels from a rarer to denser medium it bends towards the normal, the condition for total internal reflection requires the ray to bend away from the normal till 90 degree angle is attained. Hence it will not be a case of rarer to denser medium refraction.

Why is there no critical angle?

Since TIR only occurs if the refractive medium is less dense than the incident medium, the value of ni must be greater than the value of nr. If at any time the values for the numerator and denominator become accidentally switched, the critical angle value cannot be calculated.

Why is it not possible to have total internal reflection when a ray of light travels from a medium of low refractive index to a medium of high refractive index?

Since light only bends away from the normal when passing from a more dense medium into a less dense medium, then this would be a necessary condition for total internal reflection. Total internal reflection only occurs with large angles of incidence.

What happens when a ray of light travels from rarer to denser medium?

When a ray of light travels from a rarer to a denser medium, it bends towards the normal at the point of incidence. When a ray of light travels from a denser to rarer medium, it bends away from the normal at the point of incidence.

When the angle of incidence is equal to critical angle the angle of refraction is?

90°
Figure 5.15: When the angle of incidence is equal to the critical angle, the angle of refraction is equal to 90°. If the angle of incidence is bigger than this critical angle, the refracted ray will not emerge from the medium, but will be reflected back into the medium. This is called total internal reflection.

When a light travels from denser to rarer medium at the critical angle the angle of refraction is?

Critical angle for a light ray travelling from denser to rarer medium is defined as the angle of incidence at which the angle of refraction is 90°.

Why does a critical angle exist?

The critical angle occurs when the angle of incidence where the angle of refraction is \(\text{90}\)\(\text{°}\). The light must travel from an optically more dense medium to an optically less dense medium.

What happens when the angle of incidence is less than the critical angle?

As the angle of incidence increases, the angle of refraction gets closer to ninety degrees. At any angle of incidence greater than the critical angle, the light cannot pass through the surface – it is all reflected.

Are of light travels from an optically denser to rarer medium the critical angle for the two media is C?

A ray of light travels from an optically denser to rarer medium. The critical angle for the two media is C. The maximum possible deviation of the ray will be. The maximum deviation will occur in case of total internal reflection when angle of incidence is greater than the critical angle.

What is the critical angle when light travels from denser to rarer medium?

Because the light ray will bend towards the normal when light is travelling from a rarer medium to a denser medium. So there can’t be any angle such that light in denser medium goes along the surface of separation of the two media. This figure shows the critical angle when light travels from denser (medium two) to rarer medium (medium one).

How does density affect the refraction angle of light?

Light ray will always come closer to the normal (the dotted line) when travelling from rarer to denser medium. This is because the only way for light to bend away from the normal OR make an increase in its value of refraction angle is to travel from denser to rare medium.

What is the value of the critical angle at a boundary?

The actual value of the critical angle is dependent upon the combination of materials present on each side of the boundary. Let’s consider two different media – creatively named medium i (incident medium) and medium r (refractive medium). The critical angle is the Θi that gives a Θr value of 90-degrees.

What is the difference between total internal reflection and critical angle?

Past the critical angle, light is reflected rather than refracted. At any angle of incidence greater than the critical angle, the light cannot pass through the surface – it is all reflected. This is called total internal reflection.