Question

Define critical angle​

Answer 1

Explanation:

the angle of incidence beyond which rays of light passing through a denser medium to the surface of a less dense medium are no longer refracted but totally reflected.

Answer 2

Answer:

Critical Angle:

When a ray of light traveling in the denser medium enters into a rarer medium, it bends away from the normal. If the angle of incidence ‘i’ increases’ the angle of refraction ‘r’ also increases. For a particular value of the angle of incidence, the angle of refraction becomes 90°. The angle of incidence, that cause the refracted ray in the rarer medium to bend through 90° is called Critical angle.

Total Internal reflection:

When the angle of incidence becomes larger than the critical angle, no refraction occurs. The entire light is reflected back into the denser medium. This is known as the Total internal reflection of light.

Total internal reflection takes place only when:

• The light should pass from a denser medium to a rare medium.

• The angle of incidence must be greater than the critical angle.