physics paper 2 (complete) Flashcards

(143 cards)

1
Q
  1. Name the star in our solar system.
A

the sun

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2
Q
  1. How many planets in our solar system?
A

8

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3
Q
  1. What is the difference between a moon and a dwarf planet?
A

Dwarf planets orbit the sun; moons orbit planets

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4
Q
  1. What do we call the natural satellites in the solar system?
A

moons

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5
Q
  1. Name the galaxy our solar system is part of.
A

the milky way

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6
Q
  1. How was the sun formed, and what caused this to happen?
A

From a cloud of dust and gas (nebula); pulled together by

gravitational attraction; causing fusion reactions.

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7
Q
  1. List the major bodies found in the solar system.
A

Star, planets, dwarf planets, moons, asteroids, comets

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8
Q
  1. What is a nebula?
A

Could of dust and gas.

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9
Q
  1. What determines the life cycle a star will take?
A

The size of the star.

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10
Q
  1. Describe the lifecycle of a star the size of the sun.
A
Cloud of gas and dust, 
protostar, 
main sequence star, 
red giant, 
white dwarf, 
black dwarf.
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11
Q
  1. Describe the lifecycle of a star more massive than the sun.
A
cloud of gas and dust, 
protostar, 
main sequence star, 
red super giant, 
supernova, 
neutron star or black hole
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12
Q
  1. What processes produce all of the naturally occurring elements?`
A

fusion

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13
Q
  1. Where are elements heavier than iron produced?
A

supernova

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14
Q
  1. How are these elements distributed throughout the universe?
A

Explosion of massive star (supernova)

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15
Q
  1. What force enables planets and satellites to maintain their circular orbits?
A

gravity

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16
Q
  1. Main sequence stars are stable despite opposing forces acting on the star. Describe forces A and B.
A

A – gravitational attraction

B – thermal expansion

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17
Q
  1. The international space station takes 92 mins to orbit the Earth. The Moon takes 27.3 days to orbit the Earth. Explain why these orbital times are different.
A

Moon orbits at a much greater distance than the ISS; it is much
further away from the Earth.
The further from the Earth the lower the gravitational attraction
So The Moon travels slower and it takes much longer to orbit
the Earth.

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18
Q
  1. Explain how the Earth’s gravity can result in the satellites velocity changing but not its speed.
A

In a circular orbit the speed of the satellite
remains constant. Velocity is a vector so has
size AND direction.
As the direction is changing, the velocity
must be changing

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19
Q
  1. Explain why satellites in a polar orbit must travel at much higher speeds than a satellite in a geostationary orbit
A

Polar satellite are in a much lower orbit than
geostationary satellites.
In a lower orbit, gravity has a much stronger
influence so the polar satellite must travel much
faster to avoid being pulled down to Earth.

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20
Q

Which colour of light has the longest wavelength?

A

red

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21
Q

The light reaching Earth from distant galaxies exhibits red shift.
Explain why red shift occurs.

A

Galaxy is moving away at high speed
Light waves from the galaxy are being stretched to longer wavelengths.
Longer wavelengths of light are found at the red end of the spectrum.
This shift of wavelength is called red shift.

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22
Q

If galaxy A has a much bigger red shift than galaxy B, what does this
tell you about galaxy A?

A

It is travelling away at a higher speed. It is further away.

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23
Q

Which theory about the origin of the Universe does red shift of
galaxies support?

A

big bang theory

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24
Q

Describe the current theory of how the Universe began

A

Started as a small region that was very hot and dense.

Big Bang caused it to rapidly expand

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25
Atoms are only thought to make up about 5% of the known Universe. What do scientists think the remaining 95% is made up of?
Dark matter and dark energy.
26
The most distant galaxies in the Universe are thought to be,,,
accelerating
27
1. What are the poles of a magnet?
Places where the magnetic forces are strongest
28
2. When two magnets are brought together what do they do?
Exert a force on each other; attraction or repulsion.
29
3. When a magnet and a magnetic material are brought together what do they do?
attracy
30
4. What is a permanent magnet?
Material that produces its own magnetic field.
31
5. What is an induced magnet?
Material that becomes a magnet when it is placed in a | magnetic field.
32
6. Describe the difference between permanent and induced | magnets.
Permanent produces its own field/ induced becomes magnetic when placed in a field. Permanent can attract or repel/ induced always attracts. Induced magnet loses most/all of its magnetism quickly when removed from magnetic field.
33
7. Which part of a magnet has the strongest magnetic field?
poles
34
8. Two magnets are placed close together, north seeking pole to north seeking pole. Describe the forces acting on the two magnets.
repulsion
35
9. Name three magnetic elements.
Iron, steel, cobalt, nickel.
36
10. Describe two methods for finding the magnetic field pattern of a bar magnet.
Sprinkle iron filings onto paper, tap paper. Use small compasses to follow field from poles; mark paper at the compass needle end
37
12. How would you describe the direction of a magnetic field line?
Given by the direction of the force that would act on another north pole placed at that point/ from the north (seeking) pole to the south (seeking) pole.
38
13. What does a magnetic compass contain?
Small bar magnet.
39
14. Which way does the compass needle point?
In the direction of the Earth’s magnetic field.
40
15. What do scientists think is the cause of the Earth’s magnetic field?
Molten iron core.
41
1. What is produced when a current flows through a | conducting wire?
Magnetic field
42
2. Name two factors which will impact on your answer to question 1. q1 = 1. What is produced when a current flows through a conducting wire?
Magnetic field Current flowing through the wire, distance from the wire
43
3. What is a solenoid?
Coil of wire in which a magnetic field is created by passing a current though it.
44
4. Describe the magnetic field inside a solenoid.
Strong and uniform
45
5. State three ways of increasing the strength of the magnetic field produced by a solenoid
Increase the current
46
7. What is an electromagnet?
Solenoid with an iron core
47
8. (Physics only) Describe how a relay works.
A switch; uses a solenoid to attract an iron armature; small current turns on a larger current.
48
9. (Physics only) An electric bell uses a solenoid. Use the diagram below, and your own knowledge, to explain how an electric bell works .
Solenoid attracts an iron armature, breaking the circuit. Demagnetises, armature springs back. Circuit reformed. Repeat
49
10. (HT) Describe the motor effect.
Conductor carrying current placed in magnetic field; magnet and conductor exert a force on each other; this force = motor effect.
50
11. (HT) What 3 factors does Fleming’s left hand-rule represent?
The force, the current in the conductor, the magnetic field.
51
12. (HT) Give three ways of making the electric motor spin faster.
Increase the current; increase the number of turns on the coil; increase the strength of the magnets.
52
13. (HT) A 40 cm piece of wire is placed in a magnetic field of strength 0.4 T. The wire carries a current of 60 mA. Work out the force on the wire using the equation: Force = magnetic flux density x current x length.
``` 0.0096 N 40 cm = 0.4 m 60 mA = 0.06 A F = Bil F = 0.4 x 0.06 x 0.4 N ```
53
14. (Physics HT only) Explain how a loudspeaker works
A fluctuating electric current flows through the coil of wire. The coil of wire then becomes an electromagnet. The electromagnet is then attracted or repelled away from the magnet. This causes the cone to move – producing a sound.
54
1. What does the term ‘induced current’ mean?
Current made by moving a conductor relative to a magnetic | field
55
2. What is a simple generator made of?
Coil of wire; magnetic field, movement
56
3. How can the size of the induced potential difference/ | current in a generator be increased?
More turns, stronger magnetic field, increase sped of | movement
57
4. What factors affect the direction of the induced potential difference/ current?
Direction of movement/ rotation; reversing the polarity``
58
5. What type of current is induced by an alternator?
ac
59
6. What type of current is produced by a dynamo?
dc
60
7. Describe two ways of reversing the direction of current | flow on a dynamo.
Swap the polarity of both magnets. | Spin the coil of wire in the opposite direction.
61
8. At which point of the rotation does a dynamo induce the | greatest potential difference?
When the coil of wire is perpendicular to the magnetic field; it is at this point that the magnetic field lines are being cut at the greatest rate
62
9. How do microphones use the generator effect?
Convert the pressure variations in sound waves into | variations in current.
63
10. What does a basic transformer contain?
Primary coil, secondary coil, iron core
64
11. Why are cores made of iron? | ?
Easily magnetised.
65
12. What can be said about the potential difference in the | primary and secondary coils of a step-down transformer?
Vs < Vp
66
13. How do transformers work?
• Transformers have a primary coil of wire with an alternating current (ac) flowing. • This produces an alternating magnetic field in the iron core. • On the secondary side of the transformer there is a coil of wire and an alternating magnetic field. • So the magnetic field is moving relative to the coil of wire. • This induces a potential difference (and induces a current if there is a complete circuit). This is the generator effect.
67
14. A step-up transformer is used in a power station to increase the potential difference output from 25,000 V to 400,000 V. The current through the overhead power lines is 25 A. Work out the current in the primary coil. Vs × Is = Vp × Ip 15. Why are transformers used when sending electricity through the National Grid
400 A 16 times more potential difference so 16 times less current. Vs × Is = Vp × Ip or correct substitution.
68
15. Why are transformers used when sending electricity through the National Grid
Increases potential difference; decreases current; | decreases loss of energy through heat
69
1. What is a scalar quantity?
Ecalars quantities have magnitude ONLY i.e. no direction
70
2. Explain how a car can be moving at a constant speed but have changing velocity.
As velocity is a vector if the direction of the car changes the velocity will change, at a constant speed.
71
3. State whether the following quantities are scalars or vectors: Acceleration Mass Momentum Time
Acceleration Mass Momentum Time | Vector Scalar Vector Scala
72
4. Gravity is a force that acts at a distance. | Name two other forces that act at a distance.
Magnetism Electrical Force Nuclear Force
73
5. Name three contact forces.
Tension Friction (including air resistance) Normal Force
74
6. A boy has a mass of 40 kg. Calculate the boy’s weight. | Take g = 10 N/kg.
Using W = mg Substitution gives W = 40 x 10 Answer W = 400 N
75
7. Name a piece of scientific equipment that you would use to find the weight of a block in a science laboratory
NEWTONMETER
76
9. On The Moon an astronaut has a weight of 130 N. The gravitational field strength on The Moon is 1.7 N/kg. The gravitational field strength on the Earth is 10 N/kg. Calculate the weight of the astronaut on the Earth.
Using W = mg Mass of astronaut = 130 / 1.7 Mass of astronaut = 76.5 kg Using W = mg Weight of astronaut on Earth = 76.5 x 10 Weight of astronaut on Earth = 765 N
77
10. A child cuts out a picture of a snowman on a piece of card. How could you determine the centre of mass of the snowman?
Hang the picture using a pin so that the shape is free to rotate. Have a plumb line hanging from the pin. Mark the path of the plumb line against the picture. Hang the picture from another point. Mark the path again. Where the lines cross is the centre of mass of the picture.
78
1. A piano is pushed across a wooden floor with a force of 2500 N. The piano moves a distance of 3.5 m. Calculate the work done moving the piano.
Using W = F s Work done = 2500 x 3.5 Work done = 8750 J
79
2. Work done is usually measured in joules. An alternative unit for work done is (circle the correct answer). kg/m3 Nm W N/m2 N/kg
Nm
80
3. Why does a bicycle pump get hotter when used to pump up a tyre?
Work is done in compressing the air Causing the molecules to increase the frequency of their collisions Causing frictional heating and an increase in the temperature.
81
4. A box with a weight of 120 N is lifted up 1.8 m onto a shelf. Calculate the work done in lifting the box.
Using Work done = force x distance Work done = 120 x 1.8 Work done = 216 J
82
5. When a book is lifted 3 m the work done on the book is 1.2 J. Calculate the weight of the book
``` Using Work done = force x distance Rearranging gives Force = work done / distance Substitution gives Force = 12.6 / 3 Answer Force = 4.2 N ```
83
1. What type of energy is stored in a stretched spring?
Elastic Potential Energy
84
2. What is the least number of forces required to stretch a | spring?
2
85
4. A spring is stretched beyond its elastic limit. Describe the effect that this would have on the spring.
The spring would be inelastically deformed | so would not return to its original shape
86
5. Explain how the extension of a spring is determined.
The length of the extended spring | minus the original length
87
6. Motorcycles use springs for their suspension. The spring is compressed when the motorcycle rides over bumps. A force of 240 N compresses the spring 2 cm. Calculate the spring constant of the motorcycle spring
Using F = k e Rearranging gives k = F/e Substitution gives k = 240 / 0.02 Spring constant is 12 000 N/m
88
1. In a bath full of water a force of 1250 N acts on an area of 0.5 m2 at the bottom of the bath. Calculate the pressure acting on the bottom of the bath.
``` Pressure = Force / Area Pressure = 1250 / 0.5 Pressure = 2500 Pa ```
89
2. A pressure of 4000 Pa acts in a hydraulic brake fluid. The surface of the slave cylinder inside the brake system has a surface area of 0.03 m2 . Calculate the force acting on the slave cylinder
``` Pressure = Force / Area Force = Pressure x Area Force = 4000 x 0.03 Force = 120 N ```
90
3. A beaker is filled to a depth of 10 cm with water. Water has a density of 1000 kg/m3. Calculate the pressure acting at the bottom of the beaker. Take g = 10 N/kg.
Convert 10 cm into standard units: 10 cm = 0.1 m Pressure = height of column x density x gravitational field strength Pressure = 0.1 x 1000 x 10 Pressure = 1000 Pa
91
4. A scuba diver is diving in the sea. The pressure acting on the scuba diver is 267 800 Pa. Salt water has a density of 1030 kg/m3 . Calculate the depth of the scuba diver
Pressure = height of column x density x gravitational field strength Rearranging gives Height of column = Pressure / (density x gravitational field strength) Height of column = 267 800 / (1030 x 10) Height of column = 26 m Therefore the scuba diver is at a depth of 26 m.
92
5. A boat floats in sea water (density = 1030 kg/m3). The boat has a surface area of 15 m2 in contact with the water and has a pressure of 4120 Pa acting on it. Find the depth the boat floats at. Take g = 10 N/kg.
``` Pressure = height of column x gravitational field strength x density 4120 = height of column x 10 x 1030 4120 / (10 x 1030) = height of column Height of column = 0.4 m Therefore the depth of the boat is 0.4 m ```
93
6. Explain why the atmospheric pressure on the top of Mount | Everest is lower than the atmospheric pressure at sea level
At sea level there is more air above you This gives a greater weight of air pushing on you per unit area Increasing the pressure
94
1. State the typical speed of a person a) Walking b) Cycling
a) Walking 1.5 m/s b) Cycling 6 m/s
95
2. State the equation that links speed, distance and time.
SPEED = DISTANCE / TIME
96
3. Describe the difference between speed and velocity.
Speed is a scalar quantity – it has magnitude but no direction. Velocity is a vector – it has magnitude and direction
97
4. A car moves round a circular track at 120 mph. | Give the average velocity of the car. Explain your answer.
Average velocity is 0 m/s As on completion of every lap the car has a displacement of 0 m and velocity is found using displacement / time the average velocity must be 0 m/s
98
5. A motorcycle travels a distance of 420 miles in 8.5 hours. Give the average speed of the motorcycle.
``` speed = distance / time speed = 420 / 8 speed = 52.5 mph ```
99
6. Describe the difference between instantaneous speed and | average speed
Instantaneous speed is the speed at a given moment in time. Average speed is the speed over the whole journey including periods of acceleration and deceleration.
100
9. State the equation that links acceleration, change in velocity and time taken.
acceleration = change in velocity / time taken
101
10. Describe what is meant by a negative acceleration. | 10. Give the units of acceleration.
` A negative acceleration means that the object is slowing down or speeding up in the opposite direction (to that which has been assumed to be positive). 11. Give the units of acceleration. m/s2 or m/s/s or ms-2
102
12. Describe how the distance travelled by an object can be found from a velocity-time graph
The area under the line on a velocity-time graph represents the distance travelled by that object.
103
14. A stone is dropped off a cliff. The stone hits the floor at 30 m/s. Calculate the height of the cliff. Take g = 9.8 m/s2
``` Since the stone is dropped u = 0 m/s Using v 2 – u 2 = 2 a s Substituting gives 302 – 0 2 = 2 x 9.8 x s Simplifying gives 900 = 19.6 x s Rearranging gives 900 / 19.6 = s Therefore s = 45.9 m ```
104
15. Explain how the motion of a skydiver changes from the | moment they jump out of the plane until they land.
• Skydiver accelerates due to gravity (at a rate of 10 m/s2 ) • As the skydiver picks up speed the drag they experience increases • But the gravitational attraction stays the same • so the acceleration of the skydiver decreases in size. • When drag and weight are equal in size but opposite in direction the skydiver will fall with terminal speed • as there is no resultant force so no acceleration • When the parachute is opened there is an increase in drag • Decelerating the skydiver • Until weight and drag are equal in size but opposite in direction • Then the skydiver falls at a new (lower) terminal speed • Which is lower as the the large surface area of the parachute increases the amount of drag at a given speed. • Skydiver decelerates to 0 m/s when they hit the ground
105
1. Describe why a cannon ball, when fired from a cannon does not continue to move with constant velocity.
• Gravity acts pulling the cannon ball downwards • So, there is a resultant force • Objects will only continue with uniform motion when no resultant force acts.
106
2. What is the inertia of an object a measure of?
How easy, or difficult, it is to get the object to change its motion. The more inertia an object has the harder it is to get it to change its motion.
107
3. State the equation commonly used for Newton’s second law.
force = mass x acceleration
108
4. A car has a driving force of 1200 N and a mass of 700 kg. Calculate the acceleration of the car.
Using F = m a force = 700 x 1.7 force = 1190 N
109
5. A skydiver has a weight of 686 N and a mass of 70 kg. Calculate the acceleration of the skydiver the moment he jumps out of the plane.
acceleration = force / mass acceleration = 686 / 70 acceleration = 9.8 m/s2
110
6. A motorcycle has a driving force of 1400 N and an acceleration of 6 m/s2 . Calculate the mass of the motorcycle
mass = force / acceleration mass = 1400 / 6 mass = 233 kg
111
7. A father and his daughter were ice skating. The father has a mass of 75 kg and his daughter has a mass of 30 kg. The father pushed his daughter and she feels a force of 50 N. Calculate the force on the father.
50 N From Newton’s third law: whenever two objects interact, the forces they exert on each other are equal in size and opposite in direction.
112
8. A car crashed into a crash barrier. The force exerted by the barrier on the car was 4500 N. Describe the force exerted by the car onto the barrier.
The force exerted by the car onto the barrier is 4500 N. From Newton’s third law: whenever two objects interact, the forces they exert on each other are equal in size and opposite in direction.
113
1. Define thinking distance.
The distance travelled while the driver reacts to a stimulus until the driver gets their foot onto the brake pedal (but before the brake pedal is pressed).
114
2. Complete the equation: Stopping distance = ……………………………… + ……………………………….
Stopping distance = thinking distance + braking distance
115
3. Describe how the speed of a vehicle affects the thinking distance.
Increasing speed increases thinking distance | Doubling your speed doubles the thinking distance
116
break
117
6. Describe how you could measure the reaction time of a person.
• Get the person to stand with their hand open • Place a ruler at the top a the person’s hand • Drop the ruler through their hand • When the person sees the ruler move they need to close their hand • The distance the ruler travels corresponds to the thinking distance
118
7. Explain the dangers caused by large decelerations of a vehicle.
• Large decelerations can cause the brakes to overheat and become less effective • Large decelerations can also cause a loss of control • Large decelerations can also exert large forces of people within a vehicle.
119
8. whether the factor affects thinking distance, braking distance or both thinking and braking distance. Speed | Mass | Icy roads | Tiredness | Poor brakes | Mobile Phone use | Alcohol | Bald tyres |
thinking - tiredness, mobile phone use, alcohol braking distance - mass, icy roads, poor brakes, bald tyres both - speed
120
1. State the units of momentum.
kgm/s
121
2. State the equation that links mass, momentum and velocity.
Momentum = mass x velocity
122
3. Momentum is a conserved quantity. | Explain what is meant by a conserved quantity.
The momentum before and after an event is equal in a closed | system
123
4. A football has a mass of 0.75 kg and is kicked with a speed of 12 m/s. Calculate the momentum of the kicked football.
Using momentum = mass x velocity Momentum = 0.75 x 12 Momentum = 9 kgm/s
124
5. Two ice skaters push themselves apart on the ice. Explain how the conservation of momentum applies in this case.
The momentum before pushing is 0 kgm/s as they are not moving On pushing apart the momentum of each ice skater is the same size but in the opposite direction When adding (vector addition) of the momentum of the two ice skaters sum is also 0 kgm/s So momentum is conserved.
125
``` 6. A trolley has a mass of 1.2 kg and a speed of 4.5 m/s. The trolley crashes into a stationary trolley of mass 0.8 kg. On impact the two trolley’s stick together and move off with speed, v. a. Calculate the momentum of the trolleys before impact. b. Calculate the speed of the trolleys after impact. ```
``` a. Calculate the momentum of the trolleys before impact. Using momentum = mass x velocity momentum = 1.2 x 4.5 momentum = 5.4 kgm/s ``` b. Calculate the speed of the trolleys after impact. Using conservation of momentum; Momentum before = Momentum after 5.4 = massafter x velocityafter velocityafter = 5.4 / 2 = 2.7 m/s
126
7. A gymnast falls onto a crash mat. The crash mat reduces the risk of injury to the gymnast. Explain how the crash mat reduces injury.
The crash mat increases the time taken to come to a stop This decreases the acceleration Since F = m △v /△t This reduces the force acting on the gymnast
127
8. A car of mass 850 kg hits a crash barrier at a speed of 30 m/s. The car stops in 0.1 s. Calculate the force on the car
Using F = m x ( △v / △t) F = 850 x 30 0.4 F = 63 750 N
128
skip
129
4. What is meant by the period of a wave?
Time taken to complete 1 full wave.
130
5. A wave has a period of 0.25s. Calculate the frequency of this wave. T = 1 / f
f = 1/T f = 1 / 0.25 Frequency = 4Hz
131
6. A sound wave has a frequency of 240Hz and a wavelength of 1.38m. Calculate the velocity of this sound wave. Show clearly the formula you use for this calculation.
v = f λ v = 240 x 1.38 | Velocity of the wave = 331.3m/s
132
7. The diagram shows a ripple tank, used to generate waves in the laboratory. Describe the measurements that must be made in order to calculate the velocity of water waves in the tank.
Measure wave frequency with a strobe light and wavelength of a wave with a ruler then use v = f λ or: measure time for a wave to travel a measured distance and use s = d/t
133
8. (Physics HT only) The sound waves from a noisy jet travel from the air into water. Which property of the wave will not change?
Frequency.
134
9. (Physics HT only) The Eiffel Tower is made of iron. The speed of sound in iron is 4000m/s. Someone at the top hits the iron with a hammer and the sound can be heard at the bottom 0.08s later. How tall is the Eiffel Tower?
s = d/t d(height) = s x t Height = 4000 x 0.08 = 320m
135
11. (Physics only) When light strikes a black curtain, very little light gets reflected. What happens to the light?
It is absorbed by the curtain as heat energy.
136
12. (Physics only) Explain why you cannot see your reflection when you look into a piece of white plastic held in front of you.
Light rays are scattered in all directions – diffuse reflection.
137
13. (Physics only) When waves flow from deep water to shallow water the wave can bend (diffract). What happens to the speed of the wave to allow this to happen?
Waves slow down in shallow water. Bottom of wave enters shallow water before top of wave. Therefore bottom of wave slows down before the top, causing the wave to bend.
138
14. (Physics HT only) Describe how sound waves in the air are converted to vibrations in solids by the ear.
Compressions in the air cause the ear drum to flex inwards and outwards. This sets up vibrations of the bones in the inner ear.
139
15. (Physics HT only) Which of the following represents the frequency range of human hearing? 200Hz to 2000Hz 20Hz to 20 000Hz 2000Hz to 200 000Hz
20Hz to 20 000Hz
140
16. (Physics HT only) What are ultrasound waves?
Sound waves with a frequency higher than humans can hear.
141
(Physics HT only) The picture shows the ultrasound image of an unborn baby. Explain how ultrasound is able to produce an image from the outside of the mother.
Ultrasounds penetrate the body. Some of the waves are reflected when they meet a boundary between two structures. These reflected waves are received at different times and are formed into an image.
142
18. (Physics HT only)Seismic waves are described as P or S waves. Copy the table and put ticks in the correct column to show the difference in these two seismic waves.
p wave - longitudinal, fastest, can travel throigh liquid and solid
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19. (Physics HT only) Describe how P and S seismic waves can be used to show part of the Earth’s core is liquid.
Detectors on the opposite side of the Earth to the earthquake epicentre can record both P and S waves. Only P waves are detected meaning S waves can not penetrate through the Earth. As S waves can not travel through liquids, it is deduced that part of the core is liquid .