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refraction and total internal reflection

Total questions: 50

Worksheet time: 50mins

Name
Class
Date
1.

Why does the pencil appear bent?

a)

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.

b)

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.

c)

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.

d)

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.

2.

What does part #2 in the system represent?

a)

Light signals are what carries information in fiber optics

b)

Digital signals are sent through fiber optic cables

c)

Total internal reflection keeps the light inside of the cable

d)

Lasers are the source of light that we send in fiber optics

e)

Glass or plastic fiber optic cables carry information as light

3.

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

Outside is air.

a)

2.0

b)

1.7

c)

2.4

4.

Which one is true for the formation of a mirage?

a)

The light first goes through TIR and then passes through the colder layers of air to hotter layers. (TIR is total internal reflection)

b)

The light first goes through TIR after passing through the colder layers of air to hotter layers.

c)

The light first goes through TIR and then passes through the hotter layers of air to colder layers.

5.

What happens to light during total internal reflection?

a)

The angle of incidence is greater than the critical angle.

b)

The angle of reflection is the same as the critical angle.

c)

The angle of refraction is less than the critical angle.

d)

The angle of incidence is zero.

6.

Fiber optic cables work because of the principle of _____.

a)

total internal refraction

b)

incomplete internal refraction

c)

total internal reflection

d)

partial internal reflection

7.

_____ cables transmit beams of light without allowing any of the light to escape until it gets to the end of the cable.

a)

Ethernet

b)

Fiber optic

c)

Armored

d)

Coaxial

8.

Which of the following statement about optical fibre is incorrect?

a)

Light is totally internally reflected down the fibre.

b)

It is used in medical (endoscope).

c)

It is used in fibre optic communication.

d)

Angle of incidence of light in optical fibre must less than critical angle.

9.

What is total internal reflection

a)

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.

b)

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.

c)

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.

d)

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.

10.

Light travels through a glass block as shown. Which angle is the critical angle for light in the glass?

a)

A

b)

B

c)

C

d)

D

11.

When the angle of refraction is 90 °\degree  the angle of incidence is called the... 

a)

Angle of incidence

b)

Critical angle

c)

Angle of total internal reflection

d)

Angle of refraction

12.

The figure below is an optical phenomenon caused by the refraction of light. What is this effect called?

a)

Dispersion

b)

Mirage

c)

Rainbow

d)

Diffraction

13.

The critical angle is the angle of refraction in denser medium in which the angle of incidence in less dense medium is 90º.

a)

True

b)

False

14.

If the angle of incidence is larger than the critical angle of a medium, total internal reflection occurs.

a)

True

b)

False

15.

The refractive index of a glass prism is 1.9. Determine its critical angle.

a)

23o

b)

30o

c)

32º

d)

35o

16.

see image

a)

A

b)

B

c)

C

d)

D

17.

If the angle of incidence is larger than the critical angle of a medium, total internal reflection occurs.

a)

True

b)

False

18.

If the angle of incidence is larger than the critical angle of a medium, total internal reflection occurs.

a)

True

b)

False

19.

Which diagram correctly describes the critical angle c for air-water surface?

a)

A

b)

B

c)

C

d)

D

20.
The imaginary line perpendicular to a reflecting surface is called _____.
a)
crooked line
b)
parallel line
c)
angular line
d)
normal line
21.
The bending of light
a)
refraction
b)
light
c)
opaque
d)
reflection
22.
The change in ________ of light causes it to bend
a)
speed
b)
distance
c)
length
d)
color
23.

Total Internal Reflection can only occur when light is traveling from a high index to a low index

a)

True

b)

False

24.

If Total Internal Reflection occurs the light will bounce back at the same angle it came in

a)

True

b)

False

25.

If light hits at an angle larger than the critical angle it will refract and pass through the material

a)

True

b)

False

26.

Light travels from air to water (n=1.33), what is the critical angle?

a)

48.8

b)

46.4

c)

52.4

d)

not possible

27.

Refraction occurs when light changes mediums, but does not change speeds

a)

True

b)

False

28.

The higher the index of refraction, the faster light travels in that medium

a)

True

b)

False

29.

Light traveling from a low index of refraction to a higher index of refraction will get slower and bend away from the normal (refract at an larger angle)

a)

True

b)

False

30.

What is the speed of light in ice (n=1.309)

a)

2.29 * 10^8 m/s

b)

2.43 *10^ 8 m/s

c)

4.36 * 10^-9

d)

4.36 *10^8 m/s

31.

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

a)

total internal reflection occurs.

b)

angle of refraction is equal to 90 degree.

c)

light is refracted out

d)

light travel in straight line

32.

Chose the TWO conditions are NOT correct for total internal reflection to take place

a)

The incident angle should be less than the critical angle

b)

The incident angle should be greater than the critical angle

c)

Light should travel from a denser to a lighter medium

d)

Light should travel from a lighter to a denser medium

33.

see image

a)

A

b)

B

c)

C

d)

D

34.

see image

a)

A

b)

B

c)

C

d)

D

35.
What is the most prominent use of Fiber Optics today?
a)
Phones
b)
Television Screens
c)
The Internet
d)
MRI imaging
36.
Absolute refractive index of any medium is always _______.
a)
less than 1
b)
greater than 1
c)
1
d)
0
37.

In which diagram is the path of the light ray NOT correct?


(Determine if the light ray is correctly bending towards or away from normal at each boundary)


P/S: Perspex is acrylic plastic.

a)

A

b)

B

c)

C

d)

D

38.

Give a reason why the signal changes direction at A

a)

its a flat surface

b)

the density of the glass is greater than the density of the air

c)

the angle of incidence is more than 90 degrees

d)

The density of the glass is less than the density of the air

39.

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

a)

refract

b)

totally internally reflect

c)

travel along the boundary

40.

A ray of light travels from glass to air with an angle of incidence of 35o. If the critical angle is 42o what will happen at the boundary?

a)

refract

b)

totally internally reflect

c)

travel along the boundary

d)

reflect

41.

A ray of light travels from air to glass with an angle of incidence of 45o. If the critical angle is 42o what will happen at the boundary?

a)

refract

b)

totally internally reflect

c)

travel along the boundary

d)

reflect

42.
The velocity of light in vacuum is _______ m/s
a)
3x108
b)
3x1012
c)
3x106
d)
3x1010
43.
Swimming pools and the ocean look shallower than they really are due to:
a)
reflection 
b)
dispersion
c)
refraction
d)
total internal reflection
44.
The formula to calculate the refractive index is
a)
n=cv
b)
n=v/c
c)
n=c/v
d)
v=nc
45.
What is this called?
a)
refraction
b)
reflection
c)
reconstroction
d)
retraction
46.
Glass has a _____________ index of refraction than air.
a)
Equal
b)
Greater
c)
Less
d)
Impossible to say
47.
What is the index of refraction of a refractive liquid if the angle of incidence in the air is 35 degrees and the angle of refraction is 14 degrees?
a)
1.33
b)
2.21
c)
2.37
d)
1.72
48.
If the angle of incidence of light traveling through air, and then striking water is 30 degrees what is the angle of refraction? (n=1 air, n=1.33 water)
a)
15 degrees
b)
22 degrees
c)
43 degrees
d)
17 degrees
49.
A student placed a pencil in a cup of water.  The pencil appears broken because light-
a)
always travels in a straight line
b)
bends when it passes through water
c)
makes the water in the glass evaporate
d)
reflects the pencil on the water's surface
50.
a)
Reflection
b)
Refraction