6.2 Total Internal Reflection

A diver is able to see a fish behind a large rock in front of him. What is the phenomenon?

• Total internal reflection

• Mirage

• Diffraction

• Interferens

Diagram 8 shows a light ray at an air-water interface. The angle of incidence is  $\theta$  . Which of the following correctly shows the observation for an air-ice interface with the same angle of incidence?

[Given the refractive index of water and ice are 1.33 and 1.31 respectively]

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A diomand glitters under the sun due to

• refraction of light

• total internal refraction

• constructive interference of light

• destructive interference of light

The refractive index of ice is 1.31. Which of the following diagrams correctly the path of a light ray through and ice prism?

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Diagram 9 shows a transparent semi-circular block. PQ is $\frac{1}{3}$  of PQR. When a light ray propagated from Q to O (centre of semi-circle), it is refracted along OR. Find the refractive index of the medium.

• 1.15

• 1.47

• 1.56

• 2.00

Diagram 10 shows the path of a light ray from liquid medium P to a semicircular glass block of refractive index 1.5. What is the refractive index of P?

• 1.2

• 1.3

• 1.5

• 1.7

Diagram 11 shows the paths of light ray from a liquid to medium 1 and medium 2. If the refractive index of medium 1 is 1.5, what is the refractive index of medium 2?

(KBAT)

• 1.1

• 1.2

• 1.6

• 1.7