Physics Paper 2 Flashcards
1
Q
What is the main difference between scalar and vector quantities?
A
Vectors quantities have a magnitude and direction, but scalar quantities only have a magnitude.
2
Q
Vector quantities may be represented by an arrow, describe how.
A
The length of the arrow can represent the magnitude, and the direction the arrow is pointing can represent the direction of the vector quantity.
3
Q
State 3 vector quantities.
A
Any three from: force, velocity, acceleration, momentum, displacement
4
Q
State 3 scalar quantities.
A
Any three from: time, distance, speed, mass, temperature.
5
Q
Complete the sentence: “A force is a __________ or ____________ that acts on an object due to the ________________ with another object.”
A
Push, pull, interaction.
6
Q
State the condition required for a contact force to occur.
A
Two objects have to be touching.
7
Q
Other than contact forces, what other type of forces are there?
A
Non-contact forces.
8
Q
State 2 contact forces.
A
Any two from: friction, air resistance, tension in ropes, normal contact force.
9
Q
State 2 non-contact forces.
A
Any two from: magnetic force, gravitational force, electrostatic force.
10
Q
Is force a vector or scalar quantity, why?
A
It is a vector quantity because it has a magnitude and direction.
11
Q
Describe the pair of forces that exist between a chair resting on the ground.
A
The chair exerts a force on the ground, while the ground pushes back at the chair with the same force. The forces are equal but opposite.
12
Q
If two objects are interacting with forces that are equal but opposite, how would the forces be represented by arrows?
A
The arrows would be equal in length and pointing in opposite directions.
13
Q
What is weight?
A
A force acting on an object due to gravity.
14
Q
State the equation that links weight, mass and gravitational field strength.
A
weight = mass x gravitational filed strength
15
Q
What are the units of weight?
A
Newtons, N
16
Q
What units of mass are used in physics equations?
A
kilograms, kg
17
Q
What are the units of gravitational field strength?
A
N/kg
18
Q
What is meant by the term “centre of mass”?
A
A single point at which you can assume the mass is concentrated, and where the weight of an object is acting upon.
19
Q
Name the piece of equipment that can be used to measure weight.
A
A newton meter.
20
Q
What is the mass of a book which has a weight of 5.37 N on Earth where g = 9.8 N/kg?
A
5.37 / 9.8 = 0.55kg
21
Q
What is the mass of a book which has a weight of 2.07 N on Earth where g = 9.8 N/kg?
A
2.07 / 9.8 = 0.21kg
22
Q
What is the weight of a book which has a mass of 0.0881 kg on Earth where g = 9.8 N/kg ?
A
0.0881 x 9.8 = 0.86N
23
Q
What is the weight of a book which has a mass of 0.790 kg on Earth where g = 9.8 N/kg ?
A
0.79 x 9.8 = 7.742N
24
Q
What is the mass of a book which has a weight of 0.524 N on Venus where g = 8.8 N/kg?
A
0.524 / 8.8 = 0.06kg
25
What is the weight of a book which has a mass of 0.355 kg on Mercury where g = 3.6 N/kg ?
0.355 x 3.6 = 1.278N
26
What is a resultant force?
It is when a single force is used to replace a number of forces acting on an object.
27
A car has two forces acting on it. 20N east and 45N west. Calculate the resultant force.
25N west.
28
A car has two forces acting on it. 34N east and 12N west. Calculate the resultant force.
22N east.
29
State the equation that links work done, force and distance.
Work done = force x distance
30
What other phrase can be used instead of work done?
Energy transferred.
31
What are the units of work done?
J or Nm
32
Convert 15J to Nm
15Nm
33
Covert 34.6 Nm to J
34.6J
34
When work is done against frictional forces what happens to the temperature of the object?
It increases.
35
A force is applied to a box and does 4190 J of work, causing the box to move 51.4 m in the direction of the force. Calculate the size of the force.
4190 / 51.4 = 81.52N
36
A force is applied to a box and does 4930 J of work, causing the box to move 58.6 m in the direction of the force. Calculate the size of the force.
4930 / 58.6 = 84.13N
37
A force of 96.0 N is applied to a box, causing the box to move 93.4 m in the direction of the force. How much work was done moving the box?
96 x 93.4 = 8966.4J
38
A force of 28.2 N is applied to a box, causing the box to move 80.1 m in the direction of the force. How much work was done moving the box?
28.2 x 80.1 = 2258.82J
39
A force of 16.0 N is applied to a box and causes it to move in the direction of the force. The force does 1580 J of work moving the box. Calculate the distance the box moves.
1580 / 16 = 98.75m
40
A force of 72.6 N is applied to a box and causes it to move in the direction of the force. The force does 2370 J of work moving the box. Calculate the distance the box moves.
2370 / 72.6 = 32.64m
41
How many forces must be acting on an object in order for it to stretch, compress or bend?
2 or more
42
Give an example of when forces cause an object to stretch.
When you stretch an elastic band.
43
Describe what happens to an object if it only has one force acting on it.
It would move in the direction of the applied force.
44
What does the term "elastically deformed" mean?
When an object that has been stretched can revert back to its original shape and length after the forces have been removed.
45
What does the term "inelastically deformed" mean?
When an object that has been stretched can't revert back to its original shape and length after the forces have been removed.
46
Complete the following sentence: "The extension of an elastic object, such as a spring, is _________ _________________ to the force applied, provided that the limit of ______________________ is not exceeded."
Directly, proportional, proportionality
47
State the equation that links force, spring constant and extension.
force = spring constant x extension
48
State the units of spring constant.
N/m
49
A spring has a spring constant of 61.4 N/m. A force of 30.5 N is applied to it to stretch the spring. Calculate the extension of the spring.
30.5 / 61.4 = 0.50m
50
A spring has a spring constant of 151 N/m. A force of 139 N is applied to it to stretch the spring. Calculate the extension of the spring.
139 / 151 = 0.92m
51
A spring is 0.954 m long when unstretched. A force of 2.02 N is applied to the spring to stretch it to a length of 1.141 m. Calculate the spring constant of the spring.
1. 141 - 0.954 = 0.187
| 2. 02 / 0.187 = 10.8 N/m
52
A spring is 1.90 m long when unstretched. A force of 8.69 N is applied to the spring to stretch it to a length of 1.9591 m. Calculate the spring constant of the spring.
1. 9591 - 1.9 = 0.0591
| 8. 69 / 0.0591 = 147.04 N/m
53
A spring is 0.833 m long when unstretched and has a spring constant of 88.1 N/m. Calculate the force required to stretch the spring to a length of 1.697 m.
1. 697 - 0.833 = 0.864
| 88. 1 x 0.864 = 76.12N
54
A spring is 0.564 m long when unstretched and has a spring constant of 75.8 N/m. Calculate the force required to stretch the spring to a length of 1.248 m.
1. 248 - 0.564 = 0.684
| 75. 8 x 0.684 = 51.85N
55
When forces cause an object to stretch or compress, which energy store gains energy?
Elastic potential energy store.
56
Define distance.
How far an object has moved.
57
Define displacement.
Displacement includes both the distance an object moves, measured in a straight line from the start point to the finish, and the direction of that straight line.
58
Describe the difference between distance and displacement.
Distance is a scalar quantity and only has a magnitude, whereas displacement is a vector quantity and has magnitude and direction.
59
Is distance a scalar or vector quantity?
Scalar
60
Is displacement a distance or vector quantity?
Vector
61
Is speed a scalar or vector quantity?
Scalar
62
What is the typical speed of a person walking?
1.5m/s
63
What is the typical speed of a person running?
3m/s
64
What is the typical speed of a person cycling?
6m/s
65
What is the typical speed of a moving car?
25m/s
66
What is the typical speed of a moving train?
30m/s
67
What is the typical speed for a moving aeroplane?
250m/s
68
What is the typical speed for sound in air?
330m/s
69
State the equation that links speed, distance travelled and time.
distance travelled = speed x time
70
What are the units of speed?
m/s
71
A cyclist travels 63.5 m in 5.73 s. What was their average speed?
63.5 / 5.73 = 11.08 m/s
72
A cyclist travels 78.2 m in 8.78 s. What was their average speed?
78.2 / 8.78 = 8.91 m/s
73
A cyclist has a speed of 6.89 m/s and travels for 8.05 s. How far did they travel?
6.89 x 8.05 = 55.47 m
74
A cyclist has a speed of 5.31 m/s and travels for 9.61 s. How far did they travel?
5.31 x 9.61 = 51.03 m
75
A cyclist has a speed of 14.4 m/s. How long does it take them to travel 95.9 m?
95.9 / 14.4 = 6.66 s
76
A cyclist has a velocity of 8.91 m/s. How long does it take them to travel 78.2 m?
78.2 / 8.91 = 8.78 s
77
Is velocity a scalar or vector quantity, why?
It is a vector quantity because it has a magnitude and direction.
78
Define velocity.
Speed in a given direction.
79
A car is going around a roundabout at 25m/s. Explain why it has a constant speed, but its velocity is constantly changing.
It has a constant speed because it is travelling at a steady 25m/s. Its velocity is constantly changing because it is constantly changing direction. Velocity has magnitude and direction whereas speed only has magnitude.
80
For a distance time graph, how can the speed of an object be calculated?
By calculating the gradient of the line.
81
For a distance time graph, what does a straight section show?
The object is stationary.
82
For a distance time graph, what does an upwards curve show?
The object is accelerating.
83
For a distance time graph, what does a slope show?
The object is travelling at a steady speed.
84
From a distance time graph, how can you determine the speed at any particular time?
By drawing a tangent and measuring the gradient of the line.
85
State the equation that links acceleration, change in velocity and time taken.
acceleration = change in velocity / time taken
86
State the units of acceleration.
m/s2
87
Complete the sentence: "An object that slows down is __________."
Decelerating.
88
For a velocity time graph, how can the acceleration of an object be calculated?
By calculating the gradient of the line.
89
For a velocity time graph, what does a straight line show?
The object has a constant acceleration.
90
For a velocity time graph, what does a flat section show?
The object is travelling at a steady speed.
91
For a velocity time graph, what does an upwards curve show?
The object's acceleration is increasing.
92
For a velocity time graph, how can you determine the distance travelled by an object?
By calculating the area under a velocity-time graph.
93
A train initially travelling at 58.9 m/s accelerates at 4.93 m/s² and reaches a final velocity of 96.9 m/s. How long was the train accelerating for?
96.9 - 58.9 = 38
| 38/ 4.93 = 7.71 s
94
A train initially travelling at 50.5 m/s accelerates at -5.60 m/s² and reaches a final velocity of 23.4 m/s. How long was the train accelerating for?
23. 4 - 50.5 = -27.1
| - 27.1 / -5.6 = 4.84 s
95
A train accelerates from an initial velocity of 91.5 m/s to a final velocity of 23.2 m/s in a time of 9.64 s. What is the acceleration of the train?
23. 2 - 91.5 = -68.3
| - 68.3 / 9.64 = -7.09 m/s2
96
A train accelerates from an initial velocity of 58.9 m/s to a final velocity of 96.9 m/s in a time of 7.71 s. What is the acceleration of the train?
96.9 - 58.9 = 38
| 38 / 7.71 = 4.93 m/s2
97
A train travelling at 80.1 m/s accelerates at -9.10 m/s² for 3.34 s. What is the final velocity of the train?
3. 34 x -9.1 = -30.394
| 80. 1 - 30.394 = 49.71m/s
98
A train accelerates at 1.44 m/s² for 7.70 s until it reaches a final velocity of 94.5 m/s. What was the initial velocity of the train?
1. 44 x 7.7 = 11.088
| 94. 5 - 11.088 = 83.41 m/s
99
A motorbike accelerates at 9.82 m/s² from an initial velocity of 32.7 m/s to a final velocity of 76.3 m/s. Calculate the distance travelled.
76. 32 - 32.72 = 2 x 9.82 x s
4752. 4 = 19.64 x s
4752. 4 / 19.64 = s
241. 98m
100
A motorbike travels 223 m whilst accelerating from an initial velocity of 36.8 m/s to a final velocity of 68.7 m/s. What was the acceleration of the motorbike?
68. 72 - 36.82 = 2 x a x 223
3365. 45 = 446 x a
7. 55 m/s2
101
A motorbike travels 179 m whilst accelerating at 1.62 m/s² and ends up with a velocity of 31.2 m/s. What was the initial velocity of the motorbike?
31.22 - u2 = 2 x 1.62 x 179
973.44 - u2 = 579.96
-u2 = 579.96 - 973.44
-u2 = -393.48
u = √393.48
u = 19.8 m/s
102
A motorbike is initially travelling at 20.4 m/s and accelerates at 7.23 m/s² whilst travelling 209 m. What is the final velocity of the motorbike?
```
v2 - 20.42 = 2 x 7.23 x 209
v2 -416.16 = 3022.14
v2 = 3022.14 + 416.16
v2 = 3438.3
v = √3438.3
v = 58.6 m/s
```
103
Complete the following sentence: "If an object has no force propelling it along, it will always ________ down and ________________, because of ____________."
Slow, stop, friction.
104
When do frictional forces occur?
When two surfaces are in contact, or when an object passes through a fluid.
105
What are fluids?
A gas or liquid.
106
What is drag?
It is a resistive force you get in fluids.
107
What is air resistance?
It is a type of drag that occurs in air
108
How could you decrease the drag experienced by a race car?
Make it more streamlined.
109
Describe the relative sizes of the frictional forces acting on an object travelling at 30mph, and an object travelling at 70mph.
Frictional forces from fluids increase with speed, so the car travelling at 70mph will experience greater frictional forces.
110
Describe how a falling object reaches terminal velocity.
When an object starts to fall, the force of gravity is much more than the frictional forces slowing it down., so it accelerates.
As the speed increases the frictional forces increase.
This gradually reduces the acceleration until eventually the frictional forces are equal to the accelerating forces.
The object is now travelling at a stead speed and reached its terminal velocity.
111
State Newton's First Law.
If the resultant force acting on an object is zero and the object is stationary, the object remains stationary.
In addition, if the resultant force acting on an object is zero and the object is moving, it will continue to move in the same direction at the same speed.
112
Complete the sentence: "The ________ of an object will only change if a ______________ force is acting on the object."
Velocity, resultant.
113
Define inertia.
The tendency of objects to continue in their state of rest or uniform motion.
114
Describe the relative size and directions of the horizontal arrows showing the forces on an object travelling at a constant velocity.
They will be equal in size and opposite in direction.
115
A resultant force on an object would produce 5 forms of motion, state these.
```
Starting to move
Coming to a stop
Speeding up
Slowing down
Changing direction
```
116
State Newton's Second Law in words.
The acceleration of an object is proportional to the resultant force acting on the object, and inversely proportional to the mass of the object.
117
State Newton's Second Law as an equation.
Force = mass x acceleration
118
A toy car of mass 1.48 kg accelerates at 2.30 m/s². What is the resultant force on the toy car?
4.48 x 2.3 = 3.40 N
119
A toy car of mass 1.02 kg accelerates at 11.3 m/s². What is the resultant force on the toy car?
1.02 x 11.3 = 11.53 N
120
A resultant force of 2.89 N acts on a toy car of mass 0.469 kg. What is the acceleration of the toy car?
2.89 / 0.469 = 6.16 m/s2
121
A resultant force of 7.69 N acts on a toy car of mass 1.07 kg. What is the acceleration of the toy car?
7.69 / 1.07 = 7.19 m/s2
122
A resultant force of 8.92 N acts on a toy car and causes it to accelerate at 7.62 m/s². What is the mass of the toy car?
8.92 / 7.62 = 1.17 kg
123
A resultant force of 10.8 N acts on a toy car and causes it to accelerate at 9.79 m/s². What is the mass of the toy car?
10.8 / 9.79 = 1.10 kg
124
Define inertial mass.
A measure of how difficult it is to change the velocity of an object.
125
What is inertial mass define as?
The ratio of force over acceleration , force / acceleration
126
Two objects are travelling at a steady speed. How could you determine which object would require a greater effort to change its velocity?
Determine the inertial mass of each object, the object with the larger inertial mass would require a greater effort.
127
State Newton's Third Law.
When two objects interact, the forces they exert on each other are equal to and opposite.
128
Explain how a person pushing on a wall is an example of Newton's Third Law.
A man pushing on a wall exerts a force on the wall. The wall exerts a normal contact force equal to an opposite the pushing force of the man.
129
Two skaters collide with into one another while skating. Explain why this is an example of Newton's Third Law.
When both the skaters collide they will feel the same sized forces, in opposite directions, and so accelerate away from each other.
130
Define stopping distance.
Stopping distance = thinking distance + braking distance
131
Define thinking distance.
The distance a vehicle travels during the driver's reaction time.
132
Define braking distance.
The distance a vehicle travels under the braking force.
133
What is thinking distance affected by?
Speed and reaction time.
134
Assuming the braking force is kept the same, describe the relationship between the speed of a vehicle and the stopping distance.
The greater the speed of the vehicle, the greater the stopping distance.
135
A person is driving a car, he brakes when he sees a cat in the road. The thinking distance is 50m and the braking distance if 65m, calculate the stopping distance.
50 + 65 = 105m
136
A person is driving a car, he brakes when he sees a cat in the road. The braking distance is 40m and the stopping distance if 65m, calculate the thinking distance.
65 - 40 = 25m
137
A person is driving a car, he brakes when he sees a cat in the road. The stopping distance is 108m and the thinking distance if 63m, calculate the braking distance.
108 - 63 = 45m
138
Complete the sentence: "Reaction times ______ from person to person. Typical values range from ______s to _____s."
Vary, 0.2, 0.9
139
State three things that can affect a driver's reaction time.
Any three from: tiredness, drugs, alcohol, distractions.
140
Explain how speed affects braking distance.
The faster a vehicle travels they longer it takes to stop, so the further it travels. (For a given braking force)
141
Explain how weather and the road surface can affect braking distance.
If it is wet or icy, or there are leaves or oil on the road, there is less grip between the vehicle's tyres and the road, which can cause the tyres to skid, increasing braking distance.
142
Explain how the condition of a vehicle's tyres can affect braking distance.
If the tyres on the vehicles are bald, they can't get rid of water in wet conditions, this leads to them skidding and increasing braking distance.
143
Explain how the conditions of a vehicle's brakes can affect braking distance.
IF the brakes are worn or faulty, they won't be able to apply as much force as well-maintained brakes, which could be dangerous when you need to brake hard, increasing braking distance.
144
Suggest why drivers should keep a greater distance from other cars in icy conditions.
There is an increase chance of skidding, so braking distance is higher, so they should keep a greater distance to compensate for this.
145
Explain why vehicles on a motorway should keep a greater distance from the vehicle in front compared to urban roads.
Vehicles on the motorway travel at a higher speed. Braking distance increases with speed, so drivers should keep a further distance to compensate for this.
146
Explain why the temperature of a vehicle's brake increase when the driver pushes the brake pedal.
A force is applied to the brakes.
Work is done by frictional forces between the brakes and the wheels.
Energy is transferred from kinetic energy store to thermal energy store.
The temperature of the brakes increase.
147
Complete the following sentence: "The greater the ________ of a vehicle the ______________ the braking _________ needed to stop the vehicle in a certain distance."
speed, greater, force.
148
A larger braking force means a larger decelerations. What problems arise with large decelerations?
They may cause the brakes to overheat so they don't work properly, or could cause the vehicle to skid.
149
A car travelling at a typical speed makes an emergency stop to avoid hitting a hazard 25 ahead. Estimate the braking force needed to produce this deceleration. Assume the vehicle is travelling at 25m/s and has a mass of 1000kg.
```
(v2-u2) = 2 x a x s
a = (v2-u2) /2s
a = (02-252) / (2 x 25) = -12.5
```
```
f= m x a
f = 1000 x 12.5 = 12500 N
```
150
State the equation to calculate momentum.
momentum = mass x velocity
151
State the units of momentum.
kg m/s
152
A car of mass 764 kg is travelling at 11.4 m/s. What is the momentum of the car?
764 x 11.4 = 8709.6 kg m/s
153
A car of mass 665 kg is travelling at 14.1 m/s. What is the momentum of the car?
665 x 14.1 = 9376.5 kg m/s
154
A car is travelling at 12.7 m/s and has momentum of 11000 kg m/s. What is the mass of the car?
11000 / 12.7 = 866.14 kg
155
A car is travelling at 14.1 m/s and has momentum of 7840 kg m/s. What is the mass of the car?
7840 / 14.1 = 556.03 kg
156
A car of mass 890 kg is moving and has a momentum of 11100 kg m/s. What is the velocity of the car?
11100 / 890 = 12.47 m/s
157
A car of mass 870 kg is moving and has a momentum of 6330 kg m/s. What is the velocity of the car?
6330 / 870 = 7.28 m/s
158
Describe the change in momentum in a closed system before and after an event. State the name given to this.
The total momentum before an event is equal to the total momentum after an event. This is called the conservation of momentum.
159
Skater A bumps into another skater, skater B. Skater B is stationary. The skaters move off together in a straight line. Explain what happens to the velocity of each of the skaters. Use the idea of conservation of momentum.
Momentum before collision = momentum after collision.
Momentum of skater A decreases and momentum of skater B increases.
Velocity of skater A decreases and velocity of skater B increases.
160
A swimmer stands on a boat. The boat is stationary. As the swimmer dives forwards, the boat moves backwards. Use the idea of conservation of momentum to explain why the boat moves backwards.
momentum before = momentum after.
Before diving, the momentum of the swimmer and boat is zero.
After diving the swimmer has forwards momentum.
Therefore the boat has equal backwards momentum.
161
State the two types of waves.
Transverse and longitudinal waves.
162
The ripples on a water surface are an example of which type of wave?
Transverse.
163
Sound waves travelling through air are examples of which type of wave?
Longitudinal.
164
Complete the sentence: "Longitudinal waves show areas of ____________ and ______________."
compression, rarefraction.
165
Explain why a twig in a pool of water will not be displaced from its position when it encounters ripples in the water.
Ripples in water are an example of a transverse wave. The ripples (wave) on a water surface will move and not the water itself, therefore the twig only bobbles up and down and is not displaced from its position.
166
Describe the difference between transverse and longitudinal waves.
Transverse waves have oscillations at right angles to the direction of energy transfer, whereas longitudinal waves have oscillations parallel to the direction of energy transfer.
167
All electromagnetic waves are examples of which wave?
Transverse.
168
In terms of wave motion, what is amplitude?
The maximum displacement of a point on a wave away from its undisturbed position.
169
In terms of wave motion, what is wavelength?
The distance from a point on a wave to the equivalent point on the adjacent wave.
170
In terms of wave motion, what is frequency?
The number of waves passing a point each second.
171
State the equation to calculate the period of a wave.
period = 1 / frequency
172
In terms of wave motion, what is the period of a wave?
The time it takes for a full cycle of a wave.
173
What are the units of frequency?
Hertz, Hz
174
A wave has a period of 5s, calculate its frequency
0.2 Hz
175
A wave has a period of 3.5s, calculate its frequency
0.29 Hz
176
A wave has a frequency of 30 Hz, calculate its period.
0.03 s
177
A wave has a frequency of 230 Hz, calculate its period.
0.0043 s
178
State the equation that links wave speed, frequency and wavelength.
wave speed = frequency x wavelength
179
A wave has a wavelength of 6.88 m and a frequency of 1990 Hz. Calculate the speed of the wave.
1990 x 6.88 = 13691.2 m/s
180
A wave has a wavelength of 1.97 m and a frequency of 1890 Hz. Calculate the speed of the wave.
1890 x 1.97 = 3723.3
181
A wave has a wavelength of 4.37 m and a speed of 19900 m/s. Calculate the frequency of the wave.
19900 / 4.37 = 4553.78 Hz
182
A wave has a wavelength of 7.75 m and a speed of 5150 m/s. Calculate the frequency of the wave.
5150 / 7.75 = 664.52 Hz
183
A wave of frequency 731 Hz has a waves speed of 2220 m/s. Calculate the wavelength of the wave.
2220 / 731 = 3.04 m
184
A wave of frequency 2530 Hz has a waves speed of 4000 m/s. Calculate the wavelength of the wave.
4000 / 2530 = 1.58 m
185
What are electromagnetic waves?
They are transverse waves that transfer energy from the source of the waves to an absorber.
186
Complete the sentence: "Electromagnetic waves form a ____________ spectrum and all types of electromagnetic waves travel at the ____________ _______________ through a _____________ or air."
continuous, same, velocity, space.
187
From long to short wavelength, state the waves that make up the electromagnetic spectrum.
Radio, microwave, infrared, visible light, ultraviolet, X-rays and gamma rays.
188
Which electromagnetic wave has the longest wavelength?
Radio waves
189
Which electromagnetic wave has the shortest wavelength?
Gamma rays
190
Which electromagnetic wave has the highest frequency?
Gamma rays.
191
Which electromagnetic wave has the lowest frequency?
Radio waves.
192
Why electromagnetic wave can our eyes detect?
Visible light.
193
When a wave meets a boundary between two materials, what three things can happen?
The wave is absorbed, transmitted, and/or reflected.
194
A wave meets a boundary and is absorbed by the second material, explain what happens.
The wave transfers energy to the objects energy stores. Often energy is transferred to a thermal energy store, which leads to heating.
195
A wave meets a boundary and is transmitted through the second material, explain what happens.
The wave carries on travelling through the new material. This often leads to refraction.
196
A wave meets a boundary and is reflected by the second material, explain what happens.
This is where the incoming ray is neither transmitted or absorbed, but instead is 'sent back' away from the second material.
197
When a wave crosses a boundary at an angle, it can be refracted. Describe what this involves.
The wave speeds up or slows down and changes direction.
198
Describe what always happens to a wave as it crosses a boundary.
It changes speed.
199
The extent to which a wave is refracted when crossing a boundary depends on what?
On the two materials it's passing through.
200
What is the normal line?
A line drawn at right angles to a boundary.
201
Describe what happens to a wave when it bends towards the normal.
The wave slows down.
202
Describe what happens to a wave when it bends away from the normal.
The wave speeds up.
203
Complete the sentence: "The wavelength of a wave changes when it is refracted, but the _______________ stays the same."
Frequency.
204
A wave travels from air to liquid water at an angle of 30 degrees. Describe how the direction and speed of the wave changes.
The wave bends towards the normal and it slows down.
205
A wave travels from air to liquid water along the normal. Describe how the direction and speed of the wave changes.
The direction of the wave stays the same, and the wave slows down.
206
A wave travels from solid glass to air at an angle of 67 degrees. Describe how the direction and speed of the wave changes.
The wave bends away from the normal and speeds up.
207
A wave travels from solid glass to air along the normal. Describe how the direction and speed of the wave changes.
The direction of the wave stays the same and the wave speeds up.
208
State the name of the angle of the incoming ray from the normal.
The angle of incidence.
209
State the name of the angle of the refracted ray from the normal.
The angle of refraction.
210
Describe the change in positions of the wave fronts on a wavefront diagram when a wave travels from air to liquid water.
The wavefronts are closer together.
211
How can radio waves be produced?
By the oscillation of charges in electrical circuits.
212
Name the object in which charges oscillate to create radio waves.
A transmitter
213
When radio waves are observed, what may they create?
An alternating current with the same frequency as the radio wave itself.
214
What name is given to an instrument that absorbs transmitted radio waves.
A receiver.
215
Complete the following sentence: "Changes in atoms and the _________ of atoms can result in ____________________ waves being generated or absorbed over a wide _______________ range."
nuclei, electromagnetic, frequency.
216
Where do gamma rays originate from?
From changes in the nucleus of an atom.
217
Name the three types of electromagnetic radiation that can have hazardous effects on human body tissue.
Ultraviolet waves, X-rays and gamma rays.
218
Define radiation dose.
It is the measure of the risk of harm resulting from an exposure of the body to radiation.
219
What damage can ultraviolet waves cause to the body?
It can cause skin to age prematurely and increase the risk of skin cancer.
220
What damage can X-ray and gamma rays cause to the body?
They are ionising radiation that can cause mutation of genes and cancer.
221
What two main things does the risk of harm from radiation exposure depend on?
The amount of radiation exposed to, and the type of radiation.
222
Name a practical application of radio waves.
Television and radio transmission.
223
Name a practical application of microwaves.
Satellite communication and cooking food.
224
Name a practical application of infrared waves.
Electrical heaters, cooking food and infrared cameras.
225
Name a practical application of visible light.
Fibre optic communications.
226
Name a practical application of ultraviolet light.
Energy efficient lamps and sun tanning.
227
Name a practical application of X-rays and gamma rays.
Medical imaging and treatments.
228
Which region of a magnet has the strongest magnetic force?
The poles of the magnet.
229
Name the two poles of a magnet.
South and North.
230
Complete the sentence: "Two like poles _________, and two unlike poles ___________."
Repel, attract.
231
What type of force is magnetic force?
A non-contact force.
232
Which type of magnet produces its own magnetic field?
A permanent magnet.
233
What is an induced magnet?
A material that becomes a magnet when it is placed in a magnetic field?
234
What force do induced magnets always create?
Attraction.
235
When does an induced magnet lose its magnetism?
When it is removed from the magnetic field.
236
What is the difference between a permanent and induced magnet?
A permanent magnet creates its own magnetic field, whereas a induced magnet doesn't.
237
What is the definition of a magnetic field?
The area around a magnet where a force acts on another magnet or magnetic material
238
Name three magnetic materials.
Iron, nickel, cobalt and steel.
239
Complete the sentence: "The force between a magnet and a magnetic material is always one of _____________."
Attraction.
240
Which experiences a larger force, a magnetic material closer or further away from a magnet?
A magnetic material closer to a magnet.
241
Describe the direction of the magnetic field lines.
From north to south.
242
What happens to the strength of the magnetic field as you get further away from the magnet?
decreases
243
What does a magnetic compass contain?
A small bar magnet.
244
True or false? The earth has a magnetic field.
True.
245
When a current flows through a conducting wire, what is produced around the wire?
A magnetic field.
246
What factors does the strength of the magnetic field around a straight wire depend upon?
size of current, distance from wire
247
Give the name for the magnet created using a coil of wire
Solenoid
248
Where is the strongest field in an electromagnet created by a coil of wire?
Inside the coil
249
What two words describe the magnetic field within the coil of a solenoid?
Strong and uniform
250
What is an electromagnet?
A solenoid containing an iron core
251
What is an important property of a solenoid/electromagnet as a magnet
Can be switched on and off with electric current.
252
Why is an iron core added to a solenoid?
Increase the strength of the magnetic field of the solenoid.
253
What does Fleming’s left-hand rule show?
Relative orientation of the force, current in the conductor, and magnetic field for the motor effect
254
In Flemming's LH rule, the thumb gives the direction of …
Force
255
In Flemming's LH rule, the second finger gives the direction of …
Current
256
In Flemming's LH rule, the first finger gives the direction of …
Magnetic Field
257
What is the motor effect?
When a conductor carrying a current Is placed in a magnetic field, the magnet producing the field and the conductor exert a force on each other.
258
What is the symbol for magnetic flux density and what unit is it measured in?
B, tesla (T)
259
State the equation which links current, force, length of conductor and magnetic flux density
f force = magnetic flux density × current × length
260
A wire has a current of 9.69 A flowing through it. The wire is placed at right angles to a magnetic field with a flux density of 1.99 T and feels a force of 10.4 N. Calculate the length of the wire.
10. 4 = 1.99 x 9.69 x length
10. 4 = 19.2831 x length
10. 4 / 19.2831 = length
0. 54 m = length
261
A wire has a current of 6.94 A flowing through it. The wire is placed at right angles to a magnetic field with a flux density of 0.962 T and feels a force of 6.10 N. Calculate the length of the wire.
6. 1 = 0.962 x 6.94 x length
6. 1 = 6.67628 x length
6. 1 / 6.67628 = length
0. 91 m = length
262
A wire of length 0.332 m has a current of 2.32 A flowing through it. The wire is placed at right angles to a magnetic field and feels a force of 1.04 N. Calculate the magnetic flux density of the magnetic field.
1. 04 = B x 2.32 x 0.332
1. 04 = B x 0.77024
1. 04 / 0.77024 = B
1. 35 T = B
263
A wire of length 0.486 m has a current of 8.43 A flowing through it. The wire is placed at right angles to a magnetic field and feels a force of 4.55 N. Calculate the magnetic flux density of the magnetic field.
4. 55 = B x 8.43 x 0.486
4. 55 = B x 4.09698
4. 55 / 4.09698 = B
1. 11 T = B
264
A wire of length 0.198 m is placed at right angles to a magnetic field of flux density 1.22 T. The wire feels a force of 2.33 N. Calculate the current through the wire.
2. 33 = 1.22 x Current x 0.198
2. 33 = 0.24156 x Current
2. 33 / 0.24156 = Current
9. 65 A = Current
265
A wire of length 0.562 m is placed at right angles to a magnetic field of flux density 1.86 T. The wire feels a force of 0.583 N. Calculate the current through the wire.
0. 583 = 1.86 x Current x 0.562
0. 583 = 1.04532 x Current
0. 583 / 1.04532 = Current
0. 56 A = Current
266
A wire of length 0.259 m has a current of 8.32 A flowing through it. The wire is placed at right angles to a magnetic field with a flux density of 1.23 T. Calculate the force on the wire.
Force = 1.23 x 8.32 x 0.259
| 2.65 N = Force
267
A wire of length 0.608 m has a current of 8.63 A flowing through it. The wire is placed at right angles to a magnetic field with a flux density of 1.56 T. Calculate the force on the wire.
Force = 1.56 x 8.63 x 0.608
| 8.19 N = Force
268
How is a basic electric motor created?
When a coil of wire carrying a current is placed in a magnetic field, it tends to rotate.
269
State the role of a split-ring commutator.
It swaps the contacts every half-turn to keep the motor running in the same direction.
270
How can you increase the speed of an electric motor?
By increasing the current, increasing the number of turns on the coil, increasing the magnetic flux density.
271
What rule can you use to determine the direction in which a coil in an electric motor will turn?
Fleming's left-hand rule.
