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IGCSE Physics3.2.2 Refraction of lightQuestion Bank

3.2.2 Refraction of light

Question 18

[Maximum number: 1]

Which conditions are necessary for light to be totally internally reflected?

incident light

angle of incidence

is in the less dense medium

less than the critical angle

is in the less dense medium

greater than the critical angle

is in the more dense medium

less than the critical angle

is in the more dense medium

greater than the critical angle

Question 18

[Maximum number: 1]

The diagram shows a ray of light entering a glass block.

Question image

Which calculation gives the refractive index of the glass?

A

sin⁡40∘sin⁡25∘\frac{\sin 40^{\circ}}{\sin 25^{\circ}}

B

sin⁡40∘sin⁡65∘\frac{\sin 40^{\circ}}{\sin 65^{\circ}}

C

sin⁡50∘sin⁡25∘\frac{\sin 50^{\circ}}{\sin 25^{\circ}}

D

sin⁡50∘sin⁡65∘\frac{\sin 50^{\circ}}{\sin 65^{\circ}}

Question 18

[Maximum number: 1]

Optical fibres are used to transmit digital signals using infrared radiation.
The average refractive index of the fibres is 1.50 .
Which row describes a digital signal and gives the speed of infrared radiation in the fibres?

digital signal

speed of infrared radiation in the fibres
m/s\mathrm{m} / \mathrm{s}

a signal that consists
of only two values

2.0×1082.0 \times 10^{8}

a signal that consists
of only two values

4.5×1084.5 \times 10^{8}

a signal that consists of
a continuous range of values

2.0×1082.0 \times 10^{8}

a signal that consists of
a continuous range of values

4.5×1084.5 \times 10^{8}

Question 19

[Maximum number: 1]

Light in transparent plastic meets a boundary with air. Light is transmitted into the air only if the angle marked θ\theta in the diagram is greater than 36∘36^{\circ}.

Question image

What is the refractive index of the plastic?

A

0.59

B

0.81

C

1.2

D

1.7

Question 19

[Maximum number: 1]

A ray of light travels from air into a glass block.

Table

Three suggestions as to how the refractive index of glass n may be calculated are listed.
1n=VaVg1 n=\frac{V_{\mathrm{a}}}{V_{\mathrm{g}}}2n=λaλg2 n=\frac{\lambda_{\mathrm{a}}}{\lambda_{\mathrm{g}}}3n=fafg3 n=\frac{f_{\mathrm{a}}}{f_{\mathrm{g}}}

Which suggestions are correct?

A

1, 2 and 3

B

1 and 2 only

C

1 and 3 only

D

2 and 3 only

Question 19

[Maximum number: 1]

A composite block is made by joining together three transparent materials.
The diagram shows a ray of light passing through the composite block.

Question image

Which list gives the three materials in order of the speeds of light in the materials, from slowest to fastest?

A

1→2→31 \rightarrow 2 \rightarrow 3

B

1→3→21 \rightarrow 3 \rightarrow 2

C

2→1→32 \rightarrow 1 \rightarrow 3

D

2→3→12 \rightarrow 3 \rightarrow 1

Question 19

[Maximum number: 1]

A ray of light travels from air into a material, as shown.

Question image

What is the refractive index of the material?

A

1.4

B

1.5

C

1.7

D

1.9

Question 19

[Maximum number: 1]

The diagram shows a ray of light passing from air into a transparent substance.

Question image

What is the refractive index of the transparent substance?

A

1.33

B

1.29

C

0.778

D

0.750

Question 19

[Maximum number: 1]

A monochromatic ray of green light in air enters a block of glass.
Which property of the ray of light always remains the same as it moves from air to glass?

A

wavelength

B

speed

C

frequency

D

direction

Question 19

[Maximum number: 1]

Light travels from air into glass.
What is the relationship between the refractive index n of the glass, the angle of incidence i and the angle of refraction r ?

A

n=irn=\frac{i}{r}

B

n=rin=\frac{r}{i}

C

n=sin⁡isin⁡rn=\frac{\sin i}{\sin r}

D

n=sin⁡rsin⁡in=\frac{\sin r}{\sin i}

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