Check Point Worksheet on Shadows

Q1. It is night-time and the desk lamp is on. Light shines onto the key.

(a) (i) Draw one ray of light on the diagram to show the light shining from the lamp onto the key. Use a ruler. Put an arrow on the ray to show the direction of the light. 2 marks (ii) There is a patch of light on the wall. This light has been reflected from the key. Draw a reflected ray of light on the diagram. Use a ruler. 2 marks (b) There is a dark shadow on the table beside the mug. Explain how this shadow is formed. 2 marks Maximum 6 marks Q2. The diagram shows a lighthouse on a rock. It is night-time and there are boats at A, B, C, D and E moored in the water.

(a) On which boat, A, B, C, D or E, would the light from the lighthouse be brightest? 1 mark (b) Each boat makes a shadow on the water. (i) Draw a cross (X) on the diagram to show where the shadow of boat A will be. 1 mark 1 PREPARED BY PREETI MANOJ

(ii) Explain why the shadow forms there.

1 mark (c) The weather changes and the fog horn on the lighthouse makes a loud sound. On which boat, A, B, C, D or E, would the sound of the fog horn be quietest? 1 mark (d) Inside the lighthouse there is a powerful lamp and some mirrors. The diagram shows the lamp and a mirror. A ray of light from the lamp is shown. Carefully draw the ray which is reflected from the mirror. Use a ruler.

2 marks Maximum 6 marks Q3.

(a) Rockets are used to summon help from lifeboat crews. A rocket was sent high into the air above a seaside town. It exploded with a loud bang and a bright flash of light. Lisa observed the alarm flare being sent up. Which statement is correct? A: the bright flash of light was seen first B: the loud bang was heard first C: the flash of light was seen and the bang was heard at the same time 1 mark Give a reason for your answer. 1 mark 2 PREPARED BY PREETI MANOJ

(b) Some people were nearer to the rocket than Lisa. How did the sound seem to them? A: It was quieter. B: It was louder. C: It was higher pitched. D: It was lower pitched. 1 mark Maximum 3 marks 4. Thunder and lightning happen at the same time.

(a) We see the flash of lightning before we hear the thunder. Give the reason for this. 1 mark (b) Omar investigated the movement of a storm. He measured the time between seeing a flash of lightning and hearing the thunder. He did this six times. Omar put his results in a table. Flash of lightning A B C D E F Time between seeing the lightning and hearing the thunder, in seconds 8.0 5.0 3.0 9.0 13.0 16.5

Omar drew a bar chart of his results as shown below.

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(i) On the bar chart, draw a bar for flash D. Use a ruler. 1 mark (ii) Which flash of lightning was closest to Omar? 1 mark (iii) Describe how the distance between the storm and Omar changed as the storm moved between flash A and flash F. 1 mark Maximum 4 marks 5. James’s coin has rolled under a cupboard. It is dark under the cupboard, and he cannot see the coin even though the light is on. The diagram shows his problem.

(a) Explain why a shadow forms under the cupboard.

1 mark

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(b) James uses a mirror to shine light from the light bulb onto the coin. He holds the mirror so that it touches the floor at point X. (i) Draw the symbol for a mirror onto the diagram at point X to show the correct angle for him to hold the mirror at. 2 marks (ii) On the diagram, draw the ray of light from the bulb to the coin. Draw an arrow on the ray to show which way the light is travelling. Use a ruler. 2 marks (iii) What is the correct scientific term that describe the ray of light after it hits the mirror. 1 mark Maximum 6 marks 6. A pupil is observing the behaviour of a woodpecker. He uses a periscope to look over a wall at a tree, and waits for the bird to land on the trunk. The pupil can only watch one part of the tree trunk at a time.

(a) Which point on the tree trunk which he can see using the periscope in the position shown. 1 mark (b) Draw the path for a ray of light on the diagram to show how the pupil sees this point. 3 marks (c) What should the pupil do to the periscope to watch point C? 5 PREPARED BY PREETI MANOJ

1 mark Maximum 5 marks

7. The diagram below shows a ray of light hitting the surface of a mirror made from thick glass.

Part of the incident ray is reflected from the glass surface and part of it penetrates the glass and is refracted. That light is then reflected by the silver backing of the mirror glass, refracting again as it emerges back into the air. (a) (i) Give the letter that represents one reflected ray 1 mark (ii) Give the letter of one refracted ray 1 mark (b) The incident ray is brighter than ray A. Give one reason for this. 1 mark maximum 3 marks 8. Two mirrors at 90° to each other always reflect a ray of light back parallel to the incident ray. (a) 6 PREPARED BY PREETI MANOJ

(i) In the diagram below, a ray of light strikes mirror 1 at an angle of 45°. Complete the diagram to show how the mirrors reflect the ray. Use a ruler and a protractor.

1 mark (ii) In the next diagram, a ray of light strikes mirror 1 at a different angle. Complete the diagram to show how the mirrors reflect the ray. Use a ruler and a protractor.

1 mark (b) Bicycles must have a reflector fixed to the rear mudguard or to the seat. The diagram shows part of a bicycle reflector and an incident ray of light. The light passes through the flat surface and is reflected from the small ‘mirrors’.

(i) In which direction is the ray of light reflected?

1 mark (ii) At night, car drivers can easily see bicycle reflectors in the beam from their headlights. Explain why. 1 mark (iii) Why is a plane mirror not suitable as a bicycle reflector? 7 PREPARED BY PREETI MANOJ

1 mark Maximum 5 marks 9. The diagram shows two rays of light coming from a point source, reflecting in a plane mirror, and entering a person’s eye. The person sees an image of the light source at a point behind the mirror.

(a) On the diagram, draw construction lines to find the position where the image appears. Label the image I. 1 mark (b) (i) The person moves further away from the mirror. How does this affect the position of the image relative to the mirror? 1 mark (ii) The point source of light is moved closer to the mirror, How does this affect the position of the image? 1 mark The diagram below shows two rays of light coming from a small fish in some water. The rays enter a person’s eye.

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(c) The person sees an image of the fish under the water. On the diagram, draw construction lines to find the position of the image. Label the image I. 1 mark (d) In some parts of the world, people catch fish using spears. When they see the image of a fish in the water, where should they aim? 1 mark Maximum 5 marks

10. (a) The diagram shows a ray of light reflecting several times between two parallel mirrors. (i) What relationship is there between the angle of incidence for the first reflection and the angle of reflection for the last reflection? 1 mark (ii) At each reflection there is a small loss in the intensity of the light. Suggest one reason why there is a small loss in the intensity of light when it is reflected. 1 mark (b) In the diagram below, the angle of incidence has changed, but the mirrors are in the same positions. State how this change in the angle of incidence would affect the intensity of the emergent ray. Explain your answer.

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2 marks (c) The two mirrors are now moved so that they are at exactly 30 to each other. The incident ray is parallel to one of the mirrors. Draw the path of the ray of light on the diagram. Use a ruler and a protractor. Label the emergent ray and draw an arrow to show its direction. o

2 marks Maximum 6 marks 11. The diagram below shows a ray of light entering a glass block.

(a) Most of the light goes into the glass block, but some does not. What happens to the light which does not go into the glass block? 1 mark 10 PREPARED BY PREETI MANOJ

(b) As the light goes into the glass block, it changes direction. What is the name of this effect? 1 mark (c) What is the name given to ray A? 1 mark (d) What is the name given to ray B? 1 mark (e) Continue the ray out of the block into the air. 2 marks (f) What is the name given to the ray you have drawn 1 mark Total 7 marks 12. An actor is on a stage in a theatre. A spotlight is shining on him.

(a) A ray of light travels from the spotlight to the actor. (i) Which line shows the ray? Give the correct letter. 1 mark (ii) How long does the light take to travel from the spotlight to the actor? A B C D about a hundred millionth of a second about a tenth of a second about a second about ten seconds