Chapter 13 - Light - Part 3

What happens to light during total internal reflection?

• The light reflects back into the original medium at the same angle.

• The light refracts closer to the normal line.

• The light refracts farther away from the normal line.

• The light reflects at the angle it would have refracted at.

When angle of incident (i) equals to critical angle (c) if light is traveled from a denser medium to a less dense medium,

• total internal reflection occurs.

• angle of refraction is equal to 90 degree.

• light is refracted out

• light travel in straight line

Why does the pencil appear bent?

• Light rays travelling from parts of the pencil above the water bend away from the normal and appear closer to the horizontal surface, thus making the pencil appear broken.

• Light rays travelling from parts of the pencil above the water bend towards from the normal and appear closer to the horizontal surface, thus making the pencil appear broken.

• Light rays travelling from parts of the pencil under the water bend away from the normal and appear closer to the horizontal surface, thus making the pencil appear broken.

• Light rays travelling from parts of the pencil under the water bend towards from the normal and appear closer to the horizontal surface, thus making the pencil appear broken.

What is total internal reflection

• Where a wave is refracted at the boundary between a dense medium and a less dense medium when the angle of incidence is greater than the critical angle.

• Where a wave is refracted at the boundary between a dense medium and a less dense medium when the angle of incidence is smaller than the critical angle.

• Where a wave is reflected at the boundary between a dense medium and a less dense medium when the angle of incidence is greater than the critical angle.

• Where a wave is reflected at the boundary between a dense medium and a less dense medium when the angle of incidence is smaller than the critical angle.

What happens to the speed of light in a more optically dense medium?

• it slows down

• it speeds up

• stays the same because all light travels at the speed of light

When will total internal reflection occur?

• When light travels from a less dense to a more dense medium

• When the angle of incidence is smaller than the critical angle

• When the angle of incidence is greater than the critical angle

• When the light cannot pass through a medium

• Angle of incidence

• Critical angle

• Angle of total internal reflection

• Angle of refraction

For total internal reflection to occur, light must

• travel from a more dense to a less dense medium

• travel from a less dense to a more dense medium

^{What is the refractive index of a fibre optic pipe if the critical angle is 30 degree?}

^{Outside is air.}

• 2.0

• 1.7

• 2.4

Choose the correct statement that describes what happens to the ray of light if the critical angle is 48^o and the angle of incidence is 48^o

• refract

• totally internally reflect

• travel along the boundary