ScienceYear 8 Physics

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Sound and Light Topic TestTime Allowed: 50 minutes

The answers should be written on the question paper.

Attempt all of the questions.

Calculators and rulers may be used.

Name: ____________________

Teacher: __________________

TOTAL /52What have you done

well in?What could you have

worked on more?Set yourself a target

for improvement.

%

Grade

CG

Q1.

The diagram below shows part of the human ear.

          We can hear somebody speaking because sound waves enter our ears.

(a)     (i)      What do our eardrums do when sound waves reach them?

.............................................................................................................1 mark

(ii)     Sometimes a lot of wax is produced in the ear.The wax rests against the eardrum, as shown above.

         Give one reason why we cannot hear very well when our ears contain a lot of wax.

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.............................................................................................................1 mark

(b)     The table below shows the lowest and highest frequencies that five living things can hear.

livingthing

lowest frequency(Hz)

highest frequency(Hz)

human 20 20 000

sparrow 300 20 000

dog 20 45 000

cat 20 64 000

rabbit 300 42 000

(i)      Which three living things from the table cannot hear a frequency of

43 000 Hz?

.............................. and .............................. and ..............................1 mark

(ii)     From the table, choose the living thing that can hear the biggest range of frequencies.

.............................................................1 mark

Maximum 4 marks

Q2. Human hearing is sensitive to a range of loudness. The units of loudness are decibels (dB).

Table 1 shows the loudness of some sounds.

                                                 Table 1 

Sound Loudness in dB

Busy road traffic 70

Disco (at the front) 110

Normal talking 60

Personal stereo (loud)

100

Vacuum cleaner 80

Whisper 20

a) Sounds up to 80 dB cause no damage to hearing, no matter how long you listen to the sound. They are described as ‘safe sounds’.

Which sounds in Table 1 are considered ‘safe’?

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........................................................................................................................(2)

b) Damage to hearing also depends on how much time you listen to the sound each day.

The maximum time that does not cause damage to hearing is shown in Table 2.

                                                     

Table 2 

Sound loudness in dB

Time limit for exposure

Up to 80 No limit

85 8 hours

90 4 hours

95 2 hours

100 1 hour

105 30 minutes

110 15 minutes

115 7.5 minutes

120 3.75 minutes

i. Describe the pattern shown in Table 2 for increasing loudness from 85 dB.

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........................................................................................................................(2)

ii. Use data from Table 1 and Table 2 to give the maximum time you should listen to a loud personal stereo each day.

                                                         ............................................................(1)

Maximum 5 marks

Q3.Three pupils took part in an investigation into the speed of sound.All three pupils stood 1020 m from an explosion.

 

•        Sylvia wore a blindfold.

•        Paul wore ear defenders.

•        James wore a blindfold and ear defenders. He rested his head on a woodenstick pushed into the ground so that he could feel vibrations.

          The explosion produced sound and light at the same time.The table shows the speed of sound in two different materials.

 

material Speed of sound (m/s)

air 340

soil 3200

(a)     Use all the information above to help you answer parts (i) and (ii) below.

(i)      In which order would the pupils notice the explosion?

first ......................................................................................................

second ................................................................................................

third .....................................................................................................1 mark

(ii)     From the information given, calculate the time it would take for the sound totravel through the air to Sylvia.

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.......................................................................................................... s2 mark

(b)     Another pupil, Nasah, stood 2000 m away from the explosion.

(i)      The sound heard by Nasah was quieter than the sound heard by Sylvia.The further sound travels the quieter it becomes.Give the reason for this.

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.............................................................................................................1 mark

(ii)     The oscilloscope trace below represents the sound Sylvia heard.

 

         The sound Nasah heard was quieter but the pitch was the same.

         On the right-hand grid, draw the trace to show the pattern of the soundNasah heard.

2 marksMaximum 5 marks

Q4.(a)     A teacher shines a laser beam onto a classroom window. It reflects off the

window and onto a screen.

 

          On the diagram above, continue the laser beam to show its path as it reflects off the window and onto the screen. Use a ruler.Add arrows to show the direction of the laser beam.

2 marks

(b)     (i)      When a pupil plays her flute in the classroom the window vibrates.Give the reason for this.

.............................................................................................................

.............................................................................................................1 mark

(ii)     When the window vibrates, what happens to the laser beam that is reflected off the window?

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.............................................................................................................1 mark

(c)     The teacher places a microphone near the pupil as she plays her flute. The diagram below shows the pattern on an oscilloscope screen.

             

          The pupil then plays her flute at a higher pitch and more quietly.Which diagram below shows the pattern that would be seen on the oscilloscope?Tick the correct box.

 1 mark

Maximum 5 marks

Q5.The diagram below shows the shapes and positions of five glass objects.

 

          Harriet put a square of black card on top of each glass object.She shone a ray of red light onto each object.

                 

          The diagrams below show the rays of light going under the cards and coming out again.Which object is under each card? Write the correct letter below each diagram.One has been done for you.

4 marks

                      

 

 

Maximum 4 marks

Q6.Tom is doing a bungee jump from a bridge.

 

          He is attached to one end of an elastic rope.The other end of the rope is attached to the bridge.Tom jumps from the bridge.

(a)     (i)      What force makes Tom fall towards the ground?

.........................................................1 mark

(ii)     Tom does not hit the river below the bridge.What makes Tom stop falling before he hits the river?

.........................................................1 mark

(b)     The next person to do a bungee jump is Jill.

          Jill weighs less than Tom.Complete the sentence below using words from the box.

 

more than                      less than               the same as

          When Jill jumps, the rope will stretch ...........................................................

          it did when Tom jumped.1 mark

(c)     Jill’s dad watches her doing the bungee jump.He is standing a long way from the bridge.Jill shouts ‘bungee’ at the same time as she jumps off the bridge.Jill’s dad sees her jump before he hears her shout.

 

(i)      Why does Jill’s dad see her jump before he hears her shout?

...............................................................................................................

...............................................................................................................1 mark

(ii)     Tom is near Jill when she shouts. Her dad is far away.

         Complete the sentence to describe how the shout will sound to Tom compared with Jill’s dad. Use one word from the box.

 

louder                higher                lower                quieter

         The shout will sound ............................................ to Tom.1 mark

Maximum 5 marks

Q7.(a)     Peter tried to obtain a mixture of red and green light.

He used white light from a spotlight and slotted a red filter and a green filter in front of it as shown below.

 

          The diagram below represents Peter’s experiment.

 

(i)      No light reached the screen. Explain why.

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.............................................................................................................2 marks

(ii)     Peter cut a circular hole in the green filter. Describe what Peter would see on the screen.

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.............................................................................................................1 mark

(b)     Peter used two spotlights to shine a mixture of red and green light on to some red curtains.

(i)      What colour did the red curtains appear in this light?

...................................................1 mark

(ii)     Give the reasons why they appeared this colour.

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.............................................................................................................2 marks

Maximum 6 marks

Q8.(a)     The diagram below shows a fish tank.

          The surface of the water acts like a mirror.The fish can see the snail reflected in the surface of the water.

 

          Draw a ray of light which passes from the snail, and reflects from the surface, toshow how the fish can see the snail. Use a ruler.

          Put arrows on the ray of light.3 marks

(b)     Andrew is looking at the snail.

 

          When a ray of light passes from water to air it changes direction.

(i)      Draw a ray of light from the snail to Andrew to show how Andrew can seethe snail. Use a ruler.

         Put arrows on the ray of light.2 marks

(ii)     What is the name given to this change in the direction of a ray of light?

.............................................1 mark

Maximum 6 marks

Q9.          The diagram shows a boat using an echo sounder. It sends a pulse of sound waves which is reflected from the sea bottom. The reflected sound waves are detected by a sensitive microphone.

          The time between sending and receiving the pulse is 0.005 s. The device calculates the depth of the sea, using the speed of sound in sea water, which is 1500 m/s.

(a)     Calculate the depth of the sea. Show your working.

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......................................................................................................................3 marks

(b)     The boat moves into very deep water. Explain why the reflected pulse is too weak to be detected.

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......................................................................................................................1 mark

(c)     The boat’s ‘echo sounder’ could not be used in an aeroplane to measure its height above the ground unless it had been modified.

          Explain why the device will not give correct heights above the ground.

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......................................................................................................................1 mark

Maximum 5 marks

Q10.          Describe an investigation for measuring the speed of sound in air.

You may use a labelled diagram to help explain your answer.

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Maximum 6 marks.