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Edexcel ScienceiGCSE Physics

J. Light2019-2020

Name:________________Physics Teacher:______________

House CG

Year 10

Specification Checklist

3.01 use the following units: degree (°), hertz (Hz), metre (m), metre/second (m/s) and second (s)

3.02 explain the difference between longitudinal and transverse waves

3.03 know the definitions of amplitude, wavefront, frequency, wavelength and period of a wave

3.09 explain that all waves can be reflected and refracted

3.14 know that light waves are transverse waves and that they can be reflected and refracted

3.15 use the law of reflection (the angle of incidence equals the angle of reflection)

3.16 draw ray diagrams to illustrate reflection and refraction

3.17 practical: investigate the refraction of light, using rectangular blocks, semi-circular blocks and triangular prisms

3.18 know and use the relationship between refractive index, angle of incidence and angle

of refraction:

refractice index= sin(angleof incidence)sin(angle of refraction)

n= sinisin r

3.19 practical: investigate the refractive index of glass, using a glass block

3.2 describe the role of total internal reflection in transmitting information along optical fibres and in prisms

3.21 explain the meaning of critical angle c

3.22 know and use the relationship between critical angle and refractive index:

refractice index= 1sin(criticalangle)

n= 1sin c

Light – Science (Physics) 2

Key Words

Key Word Image Definition

Amplitude The height of the wave from midpoint to peak.

Critical Angle The angle of incidence where the angle of refraction = 90o. The light ray travels along the surface of the block.

Electromagnetic Spectrum

A classification of waves that all travel at the speed of light. They have both an electric and magnetic part.

Frequency The number of complete waves passing a point every second.

Hertz The unit for frequency (Hz)

Incidence The incoming ray. (IN-cidence)

Medium The substance a wave travels through.

Normal A dotted line 90o to the surface light hits. Angles are always drawn between the ray and the normal line.

Oscillation A vibration.

Optical Fibre A cable that is made out of solid glass. Light can travel through it in a similar way to a prism.

Prism A glass block that we use to bend light.

Reflection When a wave bounces off an object. (Angle of Incidence = Angle of Reflection)

Refraction When light enters a medium of different density, it changes speed and changes direction.

Refractive Index A value that shows how quickly light travels in an object. The higher the value, the slower light travels and the more it bends.


https://www.google.co.uk/url?sa=i&rct=j&q=&esrc=s&source=images&cd=&cad=rja&uact=8&ved=2ahUKEwjvrrvNocndAhVLlxoKHfQKBFwQjRx6BAgBEAU&url=http://www.assignmentpoint.com/science/physics/amplitude.html&psig=AOvVaw2vyA7KtL-cs-2uojleJYRp&ust=1537521909628608

https://www.google.co.uk/url?sa=i&rct=j&q=&esrc=s&source=images&cd=&cad=rja&uact=8&ved=2ahUKEwj179LaocndAhUK1hoKHQd1BtEQjRx6BAgBEAU&url=https://gkshortcuts.blogspot.com/2015/05/trick-to-remember-order-of-Electromagnetic-Spectrum.html&psig=AOvVaw0b70qE1HnmM5BBdgmYP78m&ust=1537521932089202

https://www.google.co.uk/url?sa=i&rct=j&q=&esrc=s&source=images&cd=&cad=rja&uact=8&ved=2ahUKEwi5rejpocndAhVMQhoKHd-rC2UQjRx6BAgBEAU&url=https://www.techdoct.com/electrical-basic/frequency-measure-frequency/&psig=AOvVaw0FZQ7u1myOSnUqH93sfquC&ust=1537521970442720

https://www.google.co.uk/url?sa=i&rct=j&q=&esrc=s&source=images&cd=&cad=rja&uact=8&ved=2ahUKEwikgLKBosndAhVGUBoKHfm8DOsQjRx6BAgBEAU&url=https://en.wikipedia.org/wiki/Heinrich_Hertz&psig=AOvVaw0mFw3iWQGBDolPDnvPbRZ4&ust=1537522018460300

https://www.google.co.uk/url?sa=i&rct=j&q=&esrc=s&source=images&cd=&cad=rja&uact=8&ved=2ahUKEwjgjZvhosndAhUszIUKHQEDA5UQjRx6BAgBEAU&url=https://owlcation.com/stem/what-is-the-particle-model&psig=AOvVaw0tOwYTwIPjytRM8trlacZR&ust=1537522222674400

1: Waves Revision

Forces and Waves Recap QuizUse the knowledge you have gained in previous topics to answer the following questions:

1. What is the mass of an object that weighs 653N?

……………… (2)

2. State Hooke’s Law

…………………………………………………………………………………………………………………………………………………………………………………… (1)

3. What is a vector quantity?

…………………………………………………………………………………………

………………………………………………………………………………………… (2)

4. What is the definition of a transverse wave?

…………………………………………………………………………………………

………………………………………………………………………………………… (2)

5. If a wave is travelling at 10m/s and has a frequency of 600Hz, what is the

wavelength?

……………… (3)

6. What is the definition of time period?

…………………………………………………………………………………………

………………………………………………………………………………………… (1)

7. What is the frequency of the wavelength below? The time base is 2ms (this means

the scale is set so that one square on the oscilloscope equals 2 milliseconds).

(4)

Score [ /15]


Learning Outcomes:

1. Identify transverse and longitudinal as the two different types of wave and that they transfer energy and information.

2. Give the definitions of the wave terms: frequency, wavelength, amplitude and time period.

3. Describe the law of reflection and demonstrate it experimentally.

Waves Summary sheet:

Transverse and Longitudinal

1. Transverse Waves: The _______________ are _____________ to the direction of ___________ transfer.

2. Longitudinal Waves: The _______________ are _____________ to the direction of ___________ transfer.

Key features of waves

Key Features Definitions

Amplitude

Frequency

Wavelength

Time Period

Equations and Prefixes

Units

v = = metres [m]f = hertz [Hz]

Name Symbol Meaning

Mega M x 106 (x 1000000)

Kilo

Centi x 10-2 (100)

f= 1T

Units

f = T =

m

Micro x 10-6 (1000000)

n x 10-9 (1000000000)

Worksheet: Waves Recap/Revision


Diagram of a Transverse Wave Diagram of a Longitudinal Wave

Use your knowledge from Shell and the summary sheet to complete the following questions.

1. Label each part of the transverse wave in the space provided:

a) …………………………

b) …………………………

c) …………………………

d) …………………………

e) …………………………

f) …………………………

Fill in the blanks:

2. In a wave, ……………………… is carried from one place to another.

3. The ………………………. is a substance/material that carries the wave.

4. The two types of waves are …………………………………… and ………………………….

5. Visible light is an example of a ……………………………………. wave.

6. Sound is an example of a ……………………………………. wave.

7. Label two wavelengths on the longitudinal wave below.

8 a). What happens to the wavelength of a wave if you double the frequency?

………………………………………………………………………………………………….

………………………………………………………………………………………………….

b) What happens to the wavelength of a wave if you halve the frequency?

………………………………………………………………………………………………….

…………………………………………………………………………………………………

9. What is the equation linking wavespeed, frequency and wavelength?

………………………………………………………………………………………………….

…………………………………………………………………………………………………

10. Calculate the wave speed (in m/s) for the following waves:


b

fe d

c

a

b

a) A sound wave in steel with a frequency of 500 Hz and a wavelength of 3.0 metres.

…………………

b) A ripple on a pond with a frequency of 2 Hz and a wavelength of 40 cm.

…………………

c) A radio wave with a wavelength of 30 m and a frequency of 10 MHz.

…………………

11. Calculate the wavelength (in metres) for the following waves:

a) A wave on a slinky spring with a frequency of 2 Hz travelling at 3 m/s.

…………………

b) An ultrasound wave with a frequency 40 kHz travelling at 1450 m/s in fatty tissue.

…………………

12. Calculate the frequency (in Hz) for the following waves:

a) A sound wave of wavelength 10 metres travelling at 340 m/s in air.

…………………

b) A wave on the sea with a speed of 8 m/s and a wavelength of 20 metres.

…………………


J1: Reflection

In this investigation you are going to investigate the relationship between the angle of incidence and the angle of reflection.

Below is how we represent a plane mirror on a diagram:

To the plane mirror above add the following:

1. An incident ray2. The normal3. Label the angle of incidence ‘i'4. A reflected ray5. Label the angle of reflection ‘r’

What do you predict will be the relationship between the angle of incidence and the angle of reflection?

……………………………………………………………………………………………………………

Method

1. Set up your apparatus as shown in the diagram using a plane mirror. 2. Mark the position of the plane mirror. 3. Shine the light ray at the plane mirror4. Use crosses to mark the path of the ray. 5. Join up crosses with a ruler6. Draw on a normal where the ray reflects off the plane mirror. 7. Measure the angle of incidence and the angle of refraction and add these to your results

table.8. Repeat the investigation for different angles of incidence.


Health and Safety Check!

Light box will get very hotduring investigation. Handle with care.

Use the space below to draw your results.

**measure all angles using a protractor**

Attempt 1 2 3 4 5

Angle of incidence [o]

Angle of reflection [o]

What is the relationship between the angle of incidence and the angle of reflection?

……………………………………………………………………………………………………………

……………………………………………………………………………………………………………


2: Refraction

Waves Recap QuizUse the knowledge you have gained last lesson and in Shell to answer the following questions.

1. If the time period of a wave is 0.2 seconds. What is the frequency of the wave?

……………… (2)

2. Add a normal to the diagram below:

(1)

3. What is the law of reflection?

…………………………………………………………………………………………

………………………………………………………………………………………… (2)

4. What is the definition of a longitudinal wave?

…………………………………………………………………………………………

………………………………………………………………………………………… (2)

5. If a wave is travelling at 25m/s and has a frequency of 20kHz, what is its

wavelength?

……………… (3)

6. What is the definition of frequency?

…………………………………………………………………………………………

………………………………………………………………………………………… (1)

Score [ /11]


Learning Outcomes:

1. Define the term ‘refraction’. 2. Identify the angle of incidence and the angle of refraction on a ray diagram.3. Sketch the path of a refracted ray through different shaped prisms.

Refraction

Key Ideas

1. In a vacuum light travels at 300 000 000m/s. It travels slower in other media. 2. When a light ray travels from air to glass (or another media) it slows down as it

crosses the boundary between the two media. 3. This change in speed may cause the light ray to change direction. 4. This change in direction is called refraction. 5. When the light slows down it is refracted towards the normal – the angle

decreases. When the light speeds up it refracts away from the normal – the angle increases.


J2: Refraction

In this investigation you are going to plot the path of a raythrough different glass prisms and measure the angle of incidence and the angle of refraction.

On the diagram below, label on the angle of refraction (r) and the angle of incidence (i).

Method

1. Set up your apparatus as shown in the diagram using a rectangular block. 2. Shine the light ray through the glass block3. Use crosses to mark the path of the ray. 4. Join up crosses with a ruler5. Draw on a normal where the ray enters the glass block6. Measure the angle of incidence and the angle of refraction and add these to your results

table7. Comment on how the speed of the light has changed as the light moves between the

mediums. 8. Repeat this for different angles of incidence and different glass prisms. 9. Stretch: Measure the angles of incidence and refraction as the light exits the prisms.




Sketch around your prisms and plot the paths of the ray in the space below:


Ray Angle of Incidence [o] Angle of Refraction [o] How has the speed of the light changed?

1

2

3

4

5

6

3: The Refractive Index


Knowledge and UnderstandingUse the knowledge you have gained since the start of Shell to answer the following questions.

1. What is the acceleration of an object that reaches 4m/s from rest in 20s?

……………… (3)

2. Draw the electrical component symbol fora. Lightbulb b. Cell

(2)

3. What is the equation linking force, pressure and area?

(1)

4. What is the definition of current?

…………………………………………………………………………………………

………………………………………………………………………………………… (1)

5. What is the mass of an object if it accelerates at 2m/s2 when an unbalanced force of

1kN is applied?

……………… (3)

6. Give 2 features that all the waves in the electromagnetic spectrum have in common.

…………………………………………………………………………………………

………………………………………………………………………………………… (2)

Score [ /12]

……………………………………………………………………………………………………………

……………………………………………………………………………………………………………

……………………………………………………………………………………………………………

……………………………………………………………………………………………………………


Learning Outcomes:

1. Define the term ‘refractive index’2. Rearrange and use the equation:

n= sin isin r

3. Carry out an investigation to discover the refractive index of glass.

The Refractive Index

Key Ideas

1. Different materials can bend rays by different amounts which we describe using a number called the refractive index.

2. The refractive index gives a measure of how much the light is slowed by the denser material

3. The refractive index can be calculated using the equation:

n= sin isin r


Worked Examples

1. Sketch the path of the light as it passes through the glass block below.

2. What is the refractive index of the material below? [You will need a protractor]

3. Diamond has a refractive index of 2.4. If the angle of incidence on a diamond is 62o what will the angle of refraction be?

4. A light ray is refracted at an angle of 22o when is travels from air into water. If the refractive index of water is 1.33, what must the angle of incidence have been?


Worksheet – The Refractive Index

Complete the questions below using the equation you have just learnt. You must show all of your working [equation, substitution, solution and units]

1. Light travels from air into an unknown material. The angle of incidence is 65o and the angle of refraction is 320. What is the refractive index of the unknown material?

…………………..

2. Light travels from air into an unknown material. The angle of refraction is 23o and the angle of incidence is 500. What is the refractive index of the unknown material?

…………………..

3. Light travels from air to Perspex. If the angle of incidence of 20o creates an angle of refraction of 8.1o, what is the refractive index of Perspex?

…………………..

4. Ice has a refractive index of 1.31. If a ray of light refracts at an angle of 23o, what was the angle of incidence?

…………………..

5. The water in the Dead Sea has a refractive index of 1.39. How much more would a ray with an angle of incidence of 50o be refracted in the Dead Sea compared to tap water (n = 1.33)?

…………………..


Use the table above to answer the following questions:

6. If the angle of incidence is 24o on a piece of ruby, what would we expect the angle of refraction to be?

…………………..

7. What angle of incidence would give an angle of refraction of 15o in rock salt?

…………………..8. What material would give an angle of refraction of 13o for an angle of incidence of

20o?

…………………..

9. A ray enters water at 30o to the surface of a pool of water. What would the angle of refraction be?[Hint: Sketch a diagram to help you]

…………………..


J3: Refractive Index

In this investigation you are going to measure the refractive index of glass.

What is the equation linking refractive index, angle of incidence and angle of refraction?

On the diagram below, label on the angle of refraction (r) and the angle of incidence (i).

Method

1. Set up your apparatus as shown in the diagram using a rectangular block. 2. Shine the light ray through the glass block3. Use crosses to mark the path of the ray. 4. Join up crosses with a ruler5. Draw on a normal where the ray enters the glass block6. Measure the angle of incidence and the angle of refraction and add these to your results

table7. Calculate the refractive

index8. Repeat steps 2 – 7 using

a different angle of incidence

9. Find an average of your results.




Sketch around your block below:

Angle of Incidence [o] Angle of Refraction [o] Refractive Index

Average Refractive Index


4: The Critical Angle and TIR

Calculations with Refractive IndexCan you use the knowledge you gained in the last lesson to answer the following questions?

1. Calculate the refractive index of Medium X which gives an angle of refraction of 27o for an angle of incidence of 48o.

………………… (3)

2. Amber has a refractive index of 1.55. What would the angle of refraction be if the angle of incidence was 58o?

………………… (3)

3. Oil has a refractive index of 1.47. What angle of incidence would produce an angle of

refraction of 25o?

………………… (3)

Score [ /9]


Learning Outcomes:

1. Define the ‘critical angle’ and ‘total internal reflection’2. Give the conditions required for total internal reflection

3. Rearrange and use the equation:

n= 1sin c

The Critical Angle and TIR

Key Ideas

1. The critical angle is the smallest possible angle of incidence at which light rays are totally internally reflected.

2. When the angle of incidence is bigger than the critical angle, light rays are totally internally reflected (TIR)

3. When the angle of incidence is smaller than the critical angle, light rays are refracted.

4. TIR only occurs when a ray of light is travelling towards a less optically dense medium (medium with a lower n)


5. The critical angle angle and refractive index are linked by the equation:

n= 1sin c

Calculating the Critical Angle

Key Ideas

1. The critical angle is the smallest possible angle of incidence at which light rays are totally internally reflected.

2. The critical angle and refractive index are linked by the equation:

n= 1sin c

Worked Examples

1. What is the critical angle of diamond which has a refractive index of 2.4?

2. What is the refractive index of a material with a critical angle of 32o?


Worksheet – The Critical Angle

Complete the questions below using the equation you have just learnt. You must show all of your working [equation, substitution, solution and units]

1. What is the critical angle of water which has a refractive index of 1.33?

…………………..2. What is the critical angle of amber which has a refractive index of 1.73?

…………………..3. An unknown substance has a refractive index of 1.5. What is the critical angle of this

substance?

…………………..4. Ethanol has a critical angle of 50o, what is its’ refractive index?

…………………..5. An unknown substance has a critical angle of 36o, what is its’ refractive index?

…………………..6. Material Y has a critical angle of 47o, what is its’ refractive index?

…………………..7. Stretch: Material X causes light to refract such that an angle of incidence of 63o

gives an angle of refraction of 45o. What will the critical angle be for Material X?


…………………..

Worked Examples: Ray Diagrams.

For each of the examples below, assume the critical angle is 35o.

Key Ideas

1. When light enters a glass prism it will refract2. Special Case: When light enters along the normal (perpendicular to the surface) it

will not refract – it does still change speed but the angle is unchanged.3. When light hits a boundary you should always measure/estimate the angle of

incidence. 4. When the angle of incidence is smaller than the critical angle, light rays are

refracted out of the prism.


5. When the angle of incidence is larger than the critical angle, light rays are reflected back into the prism (TIR)

Worksheet: Ray Diagrams

The medium of the blocks below has a critical angle of 40o. Use this piece of information to sketch the paths of the ray through each of the blocks.


5: Uses of Light

Calculations with LightCan you use the knowledge you gained in previous lessons to answer the following questions?

1. Calculate the refractive index of Medium Z which gives an angle of refraction of 30o for an angle of incidence of 52o .

………………… (3)

2. Amber has a refractive index of 1.55. What would the angle of refraction be if the angle of incidence was 48o?

………………… (3)

3. Oil has a refractive index of 1.47. What is the critical angle of oil?

………………… (3)

4. A precious gem has a critical angle of 22o. What is the refractive index of the gem?

………………… (3)

Score [ /12]


Learning Outcomes:

1. Use the critical angle to calculate the refractive index of a semi-circular prism. 2. Plot and describe the path of light through an optical fibre. 3. Research other uses for light.

J4: The Critical Angle

In this investigation you are going to attempt to find and measure the critical angle of glass.

On the diagram below, sketch the path of light you would expect if you have found the critical angle [label on the critical angle on your sketch]:

Method

1. Label the equipment in the diagram.2. Set up your apparatus as shown in the diagram using a semi-circular block. 3. Shine the light ray through the glass block such that you cause a refraction at 90o.4. Use crosses to mark the path of the ray. 5. Join up crosses with a ruler6. Draw on a normal where the ray hits the boundary7. Measure the critical angle and note down your result8. Calculate the refractive index9. Answer the conclusion questions.




Sketch around your block below:

Critical Angle [o] Refractive Index

1. How does your value for refractive index compare to your results in the previous investigation?…………………………………………………………………………………………………..…………………………………………………………………………………………………..

2. What are the limitations of this investigation?…………………………………………………………………………………………………..…………………………………………………………………………………………………..

3. What happened to the ray of light when the angle of incidence was bigger than the critical angle?

…………………………………………………………………………………………………..

4. What happened to the ray of light when the angle of incidence was smaller than the critical angle?

…………………………………………………………………………………………………..


Optical Fibres

Key Ideas

1. Optical fibres are used to transmit signals and information using light2. The centre of the fibre is made from glass with a high refractive index3. The outside of the fibre is made of a different type of glass with a lower refractive

index. 4. Due to the fibre being narrow, light always hits the boundary between the two types

of glass at an angle larger than the critical angle. 5. This causes the light to travel all the way along the fibre thanks to TIR.

Do it yourselfSketch the path of light through the optical fibre below (don’t forget to draw in your normals):


Research Task: Uses of LightUse your laptop and/or your textbook to research how light is used in the following applications.

You should attempt to use key words from the topic and diagrams are encouraged.

Stretch task: Can you find any other applications of light?

……………………………………………………………………………………………………………

……………………………………………………………………………………………………………


Endoscope

……………………………………………..

……………………………………………..

……………………………………………..

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Bicycle/Car Reflectors

……………………………………………..

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Binoculars

……………………………………………..

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……………………………………………..

……………………………………………..

……………………………………………..

……………………………………………..

Stretch Task : Dispersion

Something interesting happens to light when you put it though a triangular prism.

Describe what you see happening below:

……………………………………………………………………………………………………………

……………………………………………………………………………………………………………

……………………………………………………………………………………………………………

……………………………………………………………………………………………………………

What you are seeing is a phenomenon called ‘dispersion’.

Use your computer to research the answers to the following questions:

1. What is dispersion?2. Why does it happen?3. Would it work with light from a laser? Explain your answer.

Record your answers below:

……………………………………………………………………………………………………………

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Stretch Worksheet – Modern Day Technology using the EM Spectrum

Light is part of the Electromagnetic Spectrum.

Visit the website:

https://www.newscientist.com

Search for articles using the key term ‘Electromagnetic Spectrum Technology’

Give the name of the article:

____________________________________________________

Summarise what you have read below:

……………………………………………………………………………………………………………

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Light

Past Paper Questions

Q1. Light from an object forms an image in a plane mirror.

(a) Tick the two correct statements.

(2)


(b) (i) Use words from the box to complete the labels on the diagram below.

(2)

(ii) Write r on the diagram above to show the angle of reflection.

(1)

(Total for question = 5 marks)


Q2.

A student uses a rectangular glass block to determine the refractive index of glass.

The diagram shows a ray of red light in air as it enters the glass block at P.

The normal at P is shown as a dotted line.

(a) Complete the diagram by

drawing the ray that continues inside the block labelling the angle of incidence (i) and the angle of refraction (r) drawing the ray that leaves the block.

(4)


(b) The student measures values for the angle of incidence (i) and the angle of refraction (r).

(i) Complete the table by inserting values for sin i and sin r.

(1)

(ii) State the equation that links refractive index, angle of incidence (i) and angleof refraction (r).

(1)

(iii) Calculate the refractive index of the glass.

(2)

Refractive index = ...........................................................

(c) How should the student continue the investigation to obtain a more accurate valuefor the refractive index of glass?

(3)

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Q3.

A student is investigating refraction of light.

(a) What is refraction?

(1)

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(b) The diagram shows a ray of light travelling from air to glass.

Add labels to show the angle of incidence, i, and the angle of refraction, r.

(2)

(c) The student wants to find the refractive index of the glass.

(i) State the equation linking refractive index, angle of incidence and angle ofrefraction.

(1)


(ii) The photograph shows the apparatus the student has available.

Describe how the student should carry out the experiment.

You should include:

what the student should measure how the measurements should be made how the student should use a graph to find the refractive index. (6)

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Q4. A ray of light enters a glass block and is refracted as shown in Figure 1.

(a) Explain why the ray of light is refracted towards the normal.

(2)

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(b) Opals and diamonds are transparent stones used in jewellery.

Jewellers shape the stones so that light is reflected inside.

Figure 2 shows the path of a ray of light that enters and leaves a shaped piece of opal.

This ray of light is totally internally reflected.


(i) State the equation linking refractive index and critical angle.

(1)

(ii) The critical angle of opal is 43°.

Show that the refractive index of opal is about 1.5.

(2)

(iii) The refractive index of diamond is 2.4.

Explain why rays of light inside a diamond are more likely to be totallyinternally reflected than those inside an opal.

(3)

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Q5.

The diagram shows a light ray passing though a semicircular block of glass.

The dotted line is the normal to the surface at X.

When the light ray hits the surface as shown, all of it is reflected back inside.

(a) (i) Name the process shown in the diagram.

(2)

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(ii) What is the angle labelled θ?

(1)

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(b) The diagram shows another light ray entering a right-angled glass block.

It hits the inside surface at Y as shown.

Add to the diagram to complete the path of the ray.

(3)



Light

Spec Point Notes

Light Specification Notes

3.01 use the following units: degree (°), hertz (Hz), metre (m), metre/second (m/s) and second (s)


3.02 explain the difference between longitudinal and transverse waves


3.03 know the definitions of amplitude, wavefront, frequency, wavelength and period of a wave


3.09 explain that all waves can be reflected and refracted

3.14 know that light waves are transverse waves and that they can be reflected and

refracted

See spec points 3.02 and 3.093.15 use the law of reflection (the angle of incidence equals the angle of reflection)

3.16 draw ray diagrams to illustrate reflection and refraction


3.17 practical: investigate the refraction of light, using rectangular blocks, semi-circular

blocks and triangular prisms

See page 123.18 know and use the relationship between refractive index, angle of incidence and angle

of refraction:

Refractiveindex= sin(angleof incidence)sin (angleof refraction )

n= sin (i )sin (r )

3.19 practical: investigate the refractive index of glass, using a glass block

See page 20


3.20 describe the role of total internal reflection in transmitting information along optical

fibres and in prisms

3.21 explain the meaning of critical angle c


3.22 know and use the relationship between critical angle and refractive index:

Refractiveindex= 1sin (criticalangle )

n= 1sin (c )


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