Unit 8K: Light. Unit Menu Main Menu Equipment

Transcription

1 8K1 8K2 8K3 8K4 8K5 8K6 Unit 8K: Light How does light travel? Light travels in straight lines Light travels in straight lines: shadows Light is energy Transverse and longitudinal waves What happens when light meets an object? Transparent, translucent or opaque Optical properties of diffusers How do we see things? Vision? 8K7 Reflecting light from a yoghurt carton 8K8 Vision - accommodation 8K9 Vision - blind spot 8K10 Vision - integration time 8K11 Binocular vision field of view 8K12 Integration time: colours on a spinning top How do mirrors reflect light? 8K13 The law of reflection 8K14 Multiple reflections 8K15 The retro reflector 8K16 Mirrors How are images formed? 8K17 How to make a viewing screen 8K18 How to make a Fresnel lens holder 8K19 How to make a pinhole (shoebox) camera 8K20 Viewing a pinhole camera image 8K21 Project an image of your classroom window 8K22 Form an image of a flame 8K23 Projection of an image onto a screen I 8K24 Projection of an image onto a screen II 8K25 The overhead projector 8K26 Virtual images : a pencil trick 8K27 Make the coin disappear Can light be bent? 8K28 Refraction of light 8K29 Convergent and divergent lenses 8K30 Build a beam expander 8K31 Measuring the focal length of various lenses 8K32 Combinations of thin lenses NEXT PAGE

2 What is a spectrum? 8K33 Investigate the colour spectrum 8K34 Prisms and colour How can we change colour? 8K35 How to make a light filter 8K36 Filters 8K37 How to make white light 8K38 Mixing colours I - paints 8K39 Mixing colours II ink jet printer

3 8K Equipment list Specialised Equipment Household/stationary/market 4.5V battery Card Beaker: 250 ml Cereal packets Black card Coin Bunsen burner Coloured paper or plasticene Cables + connectors/clips Coloured sticky tape Cables and clips Crayons Cutter Elastic bands Darkened classroom Glue Digital balance Jam jar Fresnel lens holder Nail Glass or Perspex block Paper Lens set: Perspex: cylindrical Pencil Lenses: plastic fresnel Ruler: plastic Lenses: selection Ruler: transparent Light source Scissors Low voltage P/S Shoebox Magnifying glass Sticky tack Marker pen Tracing paper Microscope White card Mirrors Wooden support Motor Yoghurt carton OHP Painting equipment Perspex or glass prism Plywood or MDF (3 x 150 x 100 mm) Primary filters Print and cut following page Printer Ruler: metal Ruler: transparent Selection of filters (see expt ) Slinky Spatula Torch Tracing paper Transparency Viewing screen (see expt.) Whiteboard

4 8K1 Light travels in straight lines Torch Card Position a piece of card some distance in front of a torch and observe the 1 2 shadow cast by the card on the table. Sketch the edge of the shadow produced by the card below. Sketch the shadow produced by the edge of the card below: If light didn t travel in straight lines how would the shadow of the card appear?

5 8K2 Light travels in straight lines: shadows Torch Various objects Viewing screen (see expt 8K17) 1 Illuminate an object placed in front of your viewing screen (see expt 8K17) and observe the shadow. Move the viewing screen backwards 2 and forwards and note below what happens to the size an clearness of the shadow. What happens to the size of the shadow as you move the screen away from the object? What happens to the size of the shadow as you move the screen away from the object? Ray trace the rays through to the viewing screen to show the size of the shadow in the diagram below: Viewing screen

6 8K3 Light is energy Magnifying glass Black card Sunny day 2 Demonstrate that light energy can be transformed into heat energy by focussing light from the Sun onto a sheet of dark paper.! May catch fire. What is the energy change that takes place in this experiment? Why is black card used rather than white card? How does the magnifying glass help to increase the temperature of the card?

7 8K4 Transverse and longitudinal waves Slinky Coloured sticky tape Set up a transverse wave pulse by moving your hand to the left then 1 to the right. Attach a piece of coloured paper to the slinky and observe its motion. 2 Set up a longitudinal wave pulse by moving your hand backwards and forwards parallel to the slinky. In the transverse wave and longitudinal wave above note the direction of oscillation (vibration) of the paper marker with respect to the direction of propagation: Transverse? Direction of propagation Longitudinal? Direction of propagation Fill in the following: In a transverse wave the elements of the medium vibrate to the direction of propagation. In a longitudinal wave the elements of the medium vibrate to the direction of propagation. What type of wave is a) Sound: b) Light:

8 8K5 Transparent, translucent or opaque Torch Viewing screen (see expt 8K17) Various materials (see below) Your teacher has provided you with objects with differing optical properties. Examen them to see if they are transparent, translucent or opaque. Classify the materials provided into opaque, transparent or translucent. Use the torch to help you. Material Transparent Translucent Opaque Perspex Frosted glass Tracing paper Paper Water Milk Diluted milk Trace the rays below to help show the difference between opaque, translucent and transparent materials: Transparent Translucent Opaque

9 8K6 Optical properties of diffusers Torch Viewing screen (see expt 8K17) 1 Darken the room as well as possible. Illuminate the wall with a torch light and take note of the pattern 2 of light produced on the wall. 3 Repeat with the diffusing screen infront of the torch. Compare the illumination produced by the torch with and without the diffusing screen? Compare and the illumination of an object such as a cheese grater or pin cushion using a torch with and without a diffuser. In the diagram below draw the rays through to image plane to help explain how the diffuser works: Diffuser Image Plane What do photographers often use to obtain an even light distribution (i.e. to remove unwanted shadows) in their photographic studios?

10 8K7 Reflecting light from a yoghurt carton Torch Yoghurt carton Coloured paper or plasticene Scissors 1 Cut circles from various coloured serviettes or tissue papers. 2 Place the circle into the bottom of a white yogurt carton (with label removed). 3 Shine a torch into the yogurt carton and note the colours of its walls. What colour is the light when it leaves the torch? What colour is reflected from the tissue paper? When you shine light into the yoghurt carton what colour do its walls glow? Can you explain why?

11 Pupils 8K8 Vision - accommodation. 1.Students are to work in pairs. Each student is to observe his/her partner s eye pupils. 2.Then turn off the lights and tell them to keep looking at each other until they get accustomed to the dark (about seconds). 3. Turn the lights back on again. 4. Get them to notice the difference in pupil size. Draw the pupil diameters in the situations described below: Cornea Draw your pupil before the lights are turned off. Cornea Draw your pupil after dark accomodation. Explain why the pupil size changes: The pupil size is controlled by the iris. Label the iris and the pupil in the diagram of the eye below:

12 8K9 Vision - blind spot Paper Marker pen 1.Draw two 3mm diameter black spots about 70 mm apart on a piece of card. 2.Hold them in front of your eyes. 3.Close the left eye. Watch the left spot with the right eye (but paying attention to the right spot). 70mm 4.Move the paper backwards and forwards until the right spot disappears. Indicate the following on the diagram opposite: a) The retina. b) The optic nerve. c) The blind spot. What is the function of the retina? What causes the blind spot? In this experiment what causes the spot to disappear?

13 8K10 Vision - integration time Card Crayons Elastic bands x2 Draw two diagrams on separate cards as indicated below, stick them together and make holes with a hole punch at the top and bottom. 1 2 Attach two elastic bands at either end. Wind up the card then release it. Why does the bird appear to be inside the cage as the card spins?

14 8K11 Binocular vision field of view Estimate your binocular field of view using the following method: Look straight ahead 1. Hold out both hands in front of you and gradually move them to your side. 2. Looking straight ahead note the position of your hands the moment that they just disappear from view. What does binocular vision mean? What is the binocular field of view? What is your binocular field of view in degrees? Many grazing animals such as horses, sheep and rabbits have a much larger binocular field of view than ourselves. Use the diagram below to help explain why their binocular field of view is so large: Sheep How does their anatomy achieve this? Why do they need a large binocular field of view?

15 8K12 Integration time: colours on a spinning top Scissors Cereal packets Pencil Sticky tack Painting equipment 1 Paint a cardboard disc in equal segments with the three primary colours as indicated below: Alternatively print the discs provided on the following page and cut and stick to cardboard. 2 Push a small pencil through the centre of the disc and hold with blue tack. 3 Now spin the top you have made and note what happens to the colour as you spin it. What colour does the spinning disc appear for the following combinations of paints or inks? Combination Magenta-cyan Cyan-yellow Yellow-magenta Yellow-magenta-cyan Apparent colour Why does this happen? Sometimes as the disc is spinning you will see that the segments appear to become visible and almost stationary for a brief moment. What causes this effect?

16 8K13 The law of reflection Low voltage P/S Light source Cables + connectors/clips Mirror Template provided 1! Use a low voltage power supply. Arrange the mirror, and collimating beam from the light source on the template provided (see next page). ac dc 2 Vary the angle of incidence in 5º increments then measure the angle of reflection. I R The collimated beam is incident on the mirror shown below. Draw the beam after it has reflected from the mirror in the diagram below: Collimated light beam Norm al 0 º 20º Indicate in the diagram which is: a) the angle of incidence, I. b) the angle of reflection, R. Vary the angle of incidence (I) and measure the angle of reflection (R), noting your values in the table below. Use the template on the following page to help: Angle of incidence Iº Angle of reflection Rº What is the relationship between I and R?

17 8K13 The law of reflection Position mirror here and rotate by 5º at a time. Collimated beam from light source. 10º 20º 30º 40º 50º 50º 60º 70º 10º 20º 30º 40º

18 Mirror x2 Template provided 8K14 Multiple reflections 1 on 2 Print the template provided the following page. Position two mirrors on the template and change the angle between them in 10 degree intervals. Each time note the number of multiple reflections visible. Record your results in the table below. Angle between mirrors Temperature ºC Represent your results graphically using a histogram. What happens to the number of reflections as you reduce the angle between the mirror?

19 8K14 Multiple reflections Nº of reflections Nº of reflections 90º 80º 70º 60º 50º 40º 30º 20º Angle between mirrors 90º 80º 70º 60º 50º 40º 30º 20º Angle between mirrors

20 8K14 Multiple reflections template 10º 20º 30º 40º 50º 60º 70º 80º 90º

21 8K15 The retro reflector Low voltage P/S Light source Cables + connectors/clips Mirror x2 Position two mirrors so that they are angled at 90 degrees 1 to each other. 2 Use a ray box to produce a narrow beam and direct the beam towards the mirrors. 3 Compare the angle of the outgoing beam to that of the return beam. 4 Change the angle of the outgoing beam and repeat part three above. What is the law of reflection? angle of = angle of Use the law to trace the two rays through to the second mirror and then back away from the retro-reflector. Mirror How does the angle of the incoming beam compare with that return beam? Mirror Why is the property of retro-reflection very useful in helping to make cyclists visible to drivers at night? Sketch the direction of the reflected beam for an ordinary mirror and for a retro-reflector positioned behind the cyclist below: Ordinary mirror Retro-reflector

22 Mirror x2 Card 8K16 Mirrors 1 Draw the image of the sign in the box below. 2 Draw the image of the sign in the box below. 3 Observe the image as you move your head around - what do you notice about it. 4 Using the rules of reflection ray trace the rays opposite as they reflect off the surfaces.

23 8K17 How to make a viewing screen Cutter Pencil Metal Ruler Spatula Plywood or MDF (3 x 150 x 100 mm) Wooden support Glue Tracing paper! Teacher or Technician only. Draw and cut out a rectangular frame from a piece of 3mm plywood or hardboard. Drill small holes just inside each corner to assist in cutting process.! 150 mm Use a rough working surface. 100mm Metal ruler Cut with a sharp knife on a rough surface. Press lightly using a metal ruler as a guide and repeat until complete. 2 base Glue the frame to a wooden using wood glue.! Use a well ventilated area for gluing. 3 Cut out a piece of tracing paper and stick to the frame as shown opposite.

24 8K18 How to make a Fresnel lens holder Cutter Pencil Metal Ruler Spatula Plywood or MDF (3 x 150 x 100 mm) Wooden support Glue Elastic bands Note to teacher: Fresnel lenses are flat, lightweight, cheap and very useful for demonstrating optical principles in the teaching laboratory. This holder is designed for a 200mm focal length lens of dimensions: 95mm x 135mm! Teacher or Technician only. Draw out a rectangle inside the plywood with about a 2.5 cm margin. Drill small holes just inside each corner to assist in cutting process.! 150 mm Use a rough working surface. 130mm Metal ruler Cut with a sharp DIY knife on a rough surface. Press lightly using a metal ruler as a guide and repeat until complete. 2 base Glue the frame to a wooden using wood glue. 3 Hold the lens onto the frame with two elastic bands.

25 8K19 How to make a pinhole (shoebox) camera Cutter Scissors Metal Ruler Shoebox Glue Tracing paper Nail Elastic band 1 Draw and cut out a rectangular window on the back of a shoe box. 2 Stick tracing paper over the window using glue or sellotape.! Use a well ventilated area for gluing. 3 Make a 1mm to 1.5 mm hole in the centre of the shoe box lid with a small nail. 4 Tightly secure the lid to the box using a couple of large elastic bands.

26 Shoebox camera viewer (see previous expt) 8K20 Viewing a pinhole camera image Turn off the light and pull blinds 1 2 Position the shoe box camera down except for one window which (expt 8K19) will act as an illuminated object. some distance away from the window and observe the image. Window acts as infinity object. Ray trace the rays through from the object to the image plane: How is the image orientated w.r.t the object? Is the image formed a real or a virtual image? Is the image bright or faint? How could you adapt a shoe box to take photographs? If you intend to develop photos seek expert advice first. The chemicals involved are classed as harmful.

27 8K21 Project an image of your classroom window Magnifying glass or lens Viewing screen Move the lens towards and Turn off the light and pull the blinds 1 down except for one window which will 2 away from the screen until act as an illuminated object. you see the image of the window. Window acts as infinity object. Is the image formed a real or virtual image? How is the image orientated w.r.t the object? The paraxial rays are those that pass from the object through the centre of the lens to the image plane and are not bent by the lens. These have been drawn for you (dotted lines) below. a) Trace the other rays through to the image plane. b) Draw the image of the arrow in the image plane

28 8K22 Form an image of a flame Magnifying glass or lens Bunsen burner flame Darkened classroom 1 Darken the room as well as possible. 2 so Close the hole on a Bunsen burner that a yellow flame is produced. 3 Using a lens, project an image of the flame on a black screen as indicated below. Trace the rays from the flame to the screen in the diagram below: Screen Focal Length Focal Length 2 X Focal Length How does the image appear on the screen? The image flame should be the same size as the object flame in the arrangement above. How could you make the image of the flame larger?

29 8K23 Projection of an image onto a screen I Torch Viewing screens x2 Transparency Lens Ruler Digital balance Prepare the image to be projected by holding a transparency image to the diffusing screen with a paper clip. 1 2 Separate the transparency and the of your lens. viewing screen by 4x the focal length Turn off the light and 3 illuminate the screen with a light source such as a torch. Position the lens half way between the object and viewing screen. Trace rays from the transparency through to the image plane. The paraxial rays (those which pass through the centre of the lens) have been traced for you. Now trace the other rays through to the image: Diffuser Transparency Image Plane Focal Length Focal Length 2 X Focal Length Why is it necessary to illuminate the transparency with a diffusing screen? How could you make the projected image larger? Can you think of an optical instrument that uses this type of projection system?

30 8K24 Projection of an image onto a screen II Torch Viewing screen Lens Transparent ruler Digital balance Stand approximately 1m away from a viewing screen. Then holding a Get your partner to move the 1 2 viewing screen backwards and transparent ruler in front of a torch position a lens some distance from the ruler. forwards until you see the focussed image of the ruler. The distance from the lens to the ruler must be greater 3 than the focal length of the lens. Now try and project an image on the classroom white board. Note you cannot move the whiteboard as you did with the viewing screen above so instead you will have to move the lens until the image is in focus. Try to make the image bigger. You should find that the further the distance from the whiteboard the bigger the image. Note that each time you step back away from the whiteboard you will have to re adjust the position of the lens slightly to obtain focus. Can you think of any instruments that use this type of optical system?

31 8K25 The overhead projector OHP Whiteboard Transparency A transparency has been provided by your teacher. Switch on the OHP and adjust the lens so that the image is in focus. Calculate the magnification of the projector in this focus position. Magnification : M = Image Height Object Height focal plane optical axis object plane projector lens image plane Is the image formed by the O.H.P a real or a virtual image? Explain your answer: Is the image inverted or the right way round? Adjust the position of the lens so that the image is in focus. Then fill in the table below: Height of image Height of object Magnification (see above) What adjustments must you make in order to increase or decrease the magnification of the projector? Increase Magnification: Decrease Magnification:

32 8K25 The overhead projector: template Object Height =? Object

33 8K26 Virtual images: a pencil trick Beaker 250 ml or jam jar Pencil Move the eye from positions C to A and observe what happens to the pencil tip. A B Virtual image C Object What did you observe happen to the pencil tip as you moved your eye from C to A? What type of image is formed in this experiment, virtual or real? Explain your answer: The effect is caused because the rays leaving the pencil tip are refracted when they pass from water to air. Try to explain the effect by: a) ray tracing their paths towards the eye pupil. b) reconstructing what the brain sees. A B Virtual image C Object

34 8K27 Make the coin disappear Beaker 250 ml or jam jar Coin Place a jam jar of water on top of a coin as indicated 1 opposite. A 2 the Move your eye from A to B and watch what happens to coin. B Coin What happened to the coin as you move your eye from A to B? When your eye is at a high position you can see the coin because light passes through the bottom of the jar to the coin and reflects off of it (figure 1). However as your eye position lowers there is a particular angle when the light is no longer able to reach the coin. Instead it totally reflects from the glass-water surface (figure 2). So the coin becomes invisible. This phenomenon is called total internal reflection. Figure 1 Figure 2

35 8K28 Refraction of light Low voltage P/S Light source Cables + connectors/clips Glass or Perspex block Ruler Template provided 1 Use Position the glass block so that its surface is perpendicular to the beam of light I = 0º! ac a low voltage power supply dc 2 As you rotate the glass block measure the lateral displacementof the beam using a ruler. Ruler Use the template on the following page to help you mar the angles. I Position the rectangular prism, viewing screen and collimated light beam as indicated on the template provided (see following page). Vary the angle of incidence of the ray by 5º steps and measure the displacement of the beam at the screen. Note your readings below: Angle of incidence Iº Displacement of beam (cm) Explain how the beam of light is displaced by sketching the path of the beam through the block to the prism below:

36 10º 20º 30º Unit Menu Main Menu Equipment 8K28 Refraction of light Collimated beam from light source Position perspex block here and rotate by 5º at a time. 40º Position Screen or Ruler here Displacement from optical axis x cm

37 8K29 Convergent and divergent lenses Low voltage P/S Light source Cables + connectors/clips Perspex cylindrical lens set Template provided 1 Adjust the light source so as to produce a bundle of three parallel rays.! ac Use a low voltage power supply dc 2 Examine the effect of various combination of convergent and divergent lenses on the rays. Use the template on the following page to help Position the various cylindrical lenses provided by your teacher as shown below (see template on following page). Draw the paths of the collimated beams below and write down the focal length: Focal length = Focal length = Focal length = Focal length = Can you explain what happens in the last case when the convergent and divergent lenses are placed together?

38 8K29 Convergent and divergent lenses Three collimated beams from light source. Position lens arrangement here.

39 8K30 Build a beam expander Low voltage P/S Light source Cables + connectors/clips Perspex cylindrical lens set 1 3! Adjust the light source so as to produce a bundle of three parallel collimated rays. ac Use a low voltage power supply dc Adjust the position of the long focal length lens until the out put beam is collimated (parallel). 2 Position the short focal length lens in front of the light source. Draw the ray paths of the beams through the beam expander. Focal length = Focal length = Measure the diameters of the input and output beams and calculate the magnification of the beam expander using: H output beam M = = H output beam fl fl output lens output lens

40 8K31 Measuring the focal length of various lenses Selection of lenses Viewing screen Ruler Move the lens towards and Turn off the light and pull the blinds 1 down except for one window which will 2 away from the screen until act as an illuminated object. you see the image of the window focussed on the screen. Tree acts as infinity object. Note the position of lens when the 3 image is in focus. When the object is at infinity the rays coming from any point on the object are parallel when they enter the lens and the image formed by the lens coincides with its focal length as shown below: Finish the ray trace through to the image plane in the diagram below. Now determine the focal length of the various sample lenses provided by your teacher. Sample lens Focal length (cm)

41 8K32 Combinations of thin lenses Selection of identical fresnel lenses Fresnel lens holder (see 8K18) Viewing screen Ruler Turn off the light and pull the blinds down except for one window which will 1 2 Compare the focal lengths of one, two then three Fresnel act as an illuminated object. lenses mounted back to back. Window frame acts as infinity object. Note the position of the lens when the 3 image is in focus. The resulting focal length f R of two or three thin lenses joined together is given by the following formulas: Now confirm these formulas by measuring the focal lengths of one, two then three identical Fresnel lenses mounted together, writing down you results in the table below: Number of Fresnel lenses One Two Three Focal length (cm) The diagram below on the left shows the ray trace (from an infinity object) to image plane of one Fresnel lens. Complete the ray trace for the configuration on the right, which shows two Fresnel lenses back to back. Image Plane Fresnel lens Focal Length 2 x Fresnel lens

42 8K33 Investigate the colour spectrum Jam jar White card 1Fill jam a jam jar jar right right up to up the to the brim brim with with water water and position it it on on the edge of the a table close to a window. 2Position some white paper on the floor to observe the colour spectrum produced by the jam jar. Indicate in the chart below the colours of the visible spectrum that are produced by the jam jar in this experiment: Most refracted Least refracted Indicate which colours are transmitted when you place various pieces of coloured transparency in front of the jam jar: Red filter paper: Most refracted Least refracted Blue filter paper: Most refracted Least refracted

43 8K34 Prisms and colour Low voltage P/S Light source Cables + connectors/clips Perspex or glass prism Viewing screen Position the prisms and ray box as indicated in the diagram below.! ac Use a low voltage power supply dc Colour in the spectrum that you see on the screen in the diagram below: Collimated beam Position prism here. Which colour light is refracted: a) the most? b) the least?

44 8K35 How to make a light filter Printer Template provided Print the filter master on the following page on special transparency paper made 1 for your ink jet printer. 2 Cut a circular hole in a piece of stiff card of about 6 cm diameter. 3 Cut the filter from the transparency and stick it to the cardboard.! Use a well ventilated area for gluing. 4 Finally trim the edge of the filter.

45 8K35 How to make a light filter C, M, Y : 100, 0, 0 C, M, Y : 0,100, 0 C, M, Y : 100, 0, 0 C, M, Y : 0,100, 0 C, M, Y : 0, 0, 100 C, M, Y : 0, 0, 100

46 8K36 Filters OHP Selection of filters (see expt 8K35) Examine various combinations of primary filters on the overhead projector. Alternatively place on top of white paper. Find which colours are transmitted by the following filter combinations. Colour in the overlap. Mag Yel Mag Cyan Cyan Yel Colour transmitted: Mag Cyan Yel Colour transmitted:

47 8K37 How to make white light Three similar torches Primary filters Viewing screen (see 8K17) Elastic bands 1 Attach the three primary filters you made in expt 8K17 to three torches of equal intensity. Illuminate a viewing screen with the torches observing the overlaps produced by 2 various colour combinations. What is the colour of the overlap in each of the following combinations of light colours? Colour in the overlap in each case. Mag Yel Mag Cyan Cyan Yel Colour: Mag Cyan Yel Colour:

48 8K38 Mixing colours I - paints Painting kit Cereal packets Motor Sticky tack 4.5V battery Cables and clips 1 Paint a cardboard disc in equal segments with the three primary colours as indicated below: Alternatively print the discs provided on the following page and cut and stick to cardboard. 2 Make a small hole in centre the disc and fix it to a small 4-6v motor as shown below. Plastic reductor Blue tac R 3 Investigate the various colour combinations listed below. What colour does the spinning disc appear for the following combinations of paints or inks? Combination Magenta-cyan Cyan-yellow Yellow-magenta Yellow-magenta-cyan Apparent colour Why does this happen? Sometimes as the disc is spinning you will see that the segments appear to become visible and almost stationary for a brief moment. What causes this effect?

49 8K38 Mixing colours I - paints

50 8K39 Mixing colours II ink jet printer Microscope Print and cut following page Examine under a microscope the sample strips provided (see following page) then follow the instructions below. What are the names of the four ink colours normally found in an ink jet printer? Examine sample 1 below (which shows different intensities of magenta) under a microscope objective and draw the patterns of the dots you see in the boxes below: Explain how the ink jet printer varies the intensity of the colour it is printing: When making a new colour the printer fires two coloured ink jets onto a spot (called a pixel) the colours mix and are absorbed into the paper but there is usually a margin where they don t overlap. By analysing the margins identify the primary colours present in each colour below:

51 8K39 Mixing colours II ink jet printer mple 1 100% 60% 50% 40% 30% 20% 100% 60% 50% 40% 30% 20% 100% 60% 50% 40% 30% 20% 100% 60% 50% 40% 30% 20% 100% 60% 50% 40% 30% 20% 100% 60% 50% 40% 30% 20% 100% 60% 50% 40% 30% 20% 100% 60% 50% 40% 30% 20% mple 2 Red Blue Green Purple Red Blue Green Purple Red Blue Green Purple Red Blue Green Purple Red Blue Green Purple Red Blue Green Purple Red Blue Green Purple Red Blue Green Purple Red Blue Green Purple Red Blue Green Purple