Cambridge International AS and A Level Physics Revision Guide
These are the full revision notes which cover all topics required for the (CAIE ) Cambridge AS and A Level Physics exam. They cover all the theory parts required by the syllabus for the AS Paper 1 (Multiple Choice) and AS Paper 2 (AS Structure Questions) and A2 Paper 4 (AL Structure Questions). The...
Cambridge International AS and A
Level Physics (9702)
1
,Contents INDEX Page number
-C1. Physical Quantities and Units 4
-C2. Kinematics 5
-C3. Dynamics 7
-C4. Forces, Density and Pressure 10
-C5. Work, Energy and Power 12
-C6. Deformation of Solids 13
-C7. Waves 14
-C8. Superposition 17
-C9. Electric Fields 23
-C10. Current of Electricity 25
-C11. D.C Circuits 31
-C12. Particle and Nuclear Physics 35
2
,Contents INDEX Page number
-C1. Motion in a Circle 39
-C2. Gravitational Fields 44
-C3. Ideal Gases 48
-C4. Temperature and Thermal Properties of Materials 51
-C5. Oscillations 56
-C6. Communications 63
-C7. Electric Fields 71
-C8. Capacitance 75
-C9. Electronics 78
-C10. Magnetic Fields 88
-C11. Electromagnetic Induction 97
-C12. Alternating Currents 100
-C13. Quantum Physics 107
-C14. Particle and Nuclear Physics 115
-C15. Medical Imaging 120
3
, AS
Physical Quantities and Units
Physical Quantities: The have a numerical magnitude and a unit.
SI Base units: mass (kg), amount of substance (mol), temperature (K),
luminous intensity (cd), length (m), time (s) and current (A).
Derived Units: The consist of combinations of the base units.
E.g. Speed= Distance/ Time= m/s that’s the derived unit as distance is
measured in m and seconds in s.
Homogeneity of equations:
An equation is homogenous if it has the same base units in all of the
terms.
Prefixes and Symbols:
Prefix Symbol Multiplying factor
peta P 1015
tera T 1012
giga G 109
mega M 106
kilo k 103
deci d 10-1
centi c 10-2
milli m 10-3
micro µ 10-6
nano n 10-9
pico p 10-12
Avogadro’s constant:
Is the number of atoms in 0.012Kg of carbon-12.
This means that one mole of any substance contains 6.02 * 1023 formula
units. This is used to obtain the number of particles in a substance.
4
,Scalar: Have a magnitude and no direction. E.g. Speed, mass…
Vector: Have a magnitude and a direction. E.g. Velocity, acceleration…
To add and subtract vectors you can simply use trigonometry or
Pythagoras to find the resultant vector.
In addition to this you should know how to make graphs and tables. As
well, as making reasonable estimates of physical quantities.
Kinematics
Distance: The total length travelled by an object.
Displacement: The distance travelled in a certain direction, between 2
points.
Speed: The distance travelled per unit of time.
𝑠
Speed= Distance / Time 𝑣=
𝑡
Velocity: The change in displacement with the time.
Acceleration: The rate at which the velocity changes.
𝑣−𝑢
Average Acceleration= (final velocity-initial velocity)/ Time 𝑎=
𝑡
Displacement-time graph:
On a displacement-time graph the gradient is the velocity.
Straight line going upwards object is going at a steady velocity.
Curved line going upwards object is accelerating.
Curved line going downwards object is decelerating.
Straight line going downwards is object coming back at a constant
velocity.
Horizontal straight line the object stopped.
5
,Velocity-time Graph:
On a velocity-time graph the gradient is the acceleration.
Straight horizontal line the object is going at a constant speed.
Straight upwards line the object is accelerating uniformly.
Straight downwards line the object is decelerating uniformly.
Curved line going upwards, the object is accelerating non-uniformly.
Curved line going downwards, the object is decelerating non-uniformly.
In a speed time graph the distance travelled is the area under the curve:
Distance travelled = area under the curve= base × height.
Formulas for motion in a Straight line:
v= u + at
𝑢+𝑣
𝑠= ×𝑡
2
s= ut + 0.5at2
v2 = u2 + 2as
Acceleration of free fall: 9.81 m/s2
Experiment to determine the Acceleration of Free Fall:
1. A steel ball is held on an electromagnet.
2. When the electromagnet is switched off, the ball interrupts a beam
of light and a timer is started.
3. As the ball falls, it interrupts a second beam of light and the timer
stops.
4. Then, the vertical distance h, is plotted against the time squared t2.
Projectile motion:
The horizontal motion = constant velocity.
Vertical motion = constant acceleration as the acceleration is the pull of
gravity which is a constant 9.81 m/s2. Usually, the value of acceleration is
placed into formulas in projectile motion with a negative sign as its force
acts downwards. They have a curved trajectory.
6
, Dynamics
Mass: is a measure of the amount of matter in a body and has as a
property of a body, that it resists the change in motion.
Weight: The force produced on a body due to a gravitational field.
𝑊 = 𝑚𝑔
Heavier objects fall faster with air resistance than lighter objects.
Terminal Velocity: Is the maximum velocity a body reaches through a fluid
when the net force acting on it is zero.
Formula for Force:
𝐹 = 𝑚𝑎
Force: It can be defined as the rate of change in momentum.
𝑚𝑣−𝑚𝑢
So, 𝐹 =
𝑡
Newtons First Law of motion:
If a body is at rest, it will remain stationary or if it is in motion, it will keep
moving with a uniform velocity in a straight line, until it is acted on by
resultant force.
Newtons Second Law of motion:
The rate of change in momentum of the body is directly proportional to
the resultant force applied and occurs in the direction of the force.
Newtons Third Law of motion:
When 2 bodies interact, the forces they exert on each other are equal in
magnitude but in opposite directions. This is known as an action- reaction.
Newton: Is the force that will give a 1kg mass an acceleration of 1m/s2 in
the direction of the force.
7
,Linear Momentum:
Linear momentum is defined as the product of mass and velocity. It is a
vector quantity.
𝑝 = 𝑚𝑣
p is linear momentum and the units are kgm/s.
Principal of Conservation of Momentum:
For a closed system, in any direction:
Total momentum of objects before collision = Total momentum of objects
after collision.
Perfectly Elastic Collisions:
Total momentum conserved and the total kinetic energy is conserved.
Example: Two identical objects A and B, moving at the same speed but in
opposite directions, have a head on collision. After the collision, each
object bounces back with its velocity reversed.
(Relative velocity of approach) = − (Relative velocity of separation)
Perfectly Inelastic collisions:
In inelastic collisions, total energy is conserved but kinetic energy may be
converted into other forms of energy e.g. heat.
Example: Two objects collide, but this time they stick together after the
collision and come to a halt. In this case the momentum is conserved but
the kinetic energy isn’t. Some of the kinetic energy is lost and used to
deform the object or to create sound.
8
,Collisions in 2 Dimensions:
Example Problem:
There are 2 balls before a collision. Ball 1 is moving at 4m/s and ball 2 is
stationary. They have the same mass. After the collision, ball 1, bounces
30 degrees to the left and ball 2 bounces 60 degrees to the right. Calculate
the velocities of each ball after the collision.
Horizontal motion:
Vertical motion:
Solving by Simultaneous Equations:
9
, Forces, Density and Pressure
Forces on a Charge in Electric Fields: a region of space where a charge
experiences an attractive or repulsive force due to the presence of
another charge.
Forces on Masses in Gravitational Fields: a region of space in which a
mass experiences an attractive force due to the presence of another mass.
Upthrust: an upward force exerted by a fluid on a submerged or floating
object.
Origin of Upthrust:
The difference in pressure between the top and the bottom of the object
produces an upward force on it. As the pressure at the bottom is higher
than at the top, the resultant force act upwards.
Frictional force: The force that arises when two surfaces rub.
Always opposes the motion. Always acts along a surface.
Viscous forces: A force that opposes the motion of an object in a fluid.
Only exists when there is motion. Its magnitude increases with the speed
of the object.
Centre of gravity: Is the point where all the weight of the object may be
considered to act.
Moment of a Force: product of the force and the perpendicular distance
of its line of action to the pivot.
𝑀𝑜𝑚𝑒𝑛𝑡 𝑜𝑓 𝑎 𝐹𝑜𝑟𝑐𝑒 = 𝐹𝑑𝑠𝑖𝑛𝜃
Where F is the Force in N and ⅆ 𝑠𝑖𝑛 𝜃 is the perpendicular distance in m.
Couple: a pair of forces which only produce a rotation.
Torque of a Couple: The product of one of the forces of the couple and
the perpendicular distance between the lines of action of the forces.
Torque = One of the Forces × Perpendicular Distance between Forces
Principle of Moments: for any object that is in equilibrium, the sum of all
the anticlockwise moments about any point must be equal to the sum of
all the clockwise moments about that same point.
10
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