Physics Notes

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Pure Physics SA2 Overall Revision Notes

General Physics: Chapter 1

Measurement

Physical Quantities Derived quantities (combining suitable base quantities) E.g. Velocity

Base quantity Name of SI unit Symbol

Length Metre M

Mass Kilogram Kg

Time Second S

Electric current Ampere A

Thermodynamic temperature

Kelvin K

Luminous intensity Candela Cd

Amount of substance Mole mol

Measurement of Length

Very short (diameter of small wire)

Micrometer Screw Gauge

0.01mm (0.001cm)

Short (diameter of coin)

Vernier Calipers

0.01cm

Medium (Length of pendulum)

Metre Rule 0.1cm

Long (Length of vehicles)

Measuring tape

1cm

Vernier Calipers: Total the values of the main scale and vernier scale readings to obtain the correct reading. Remember to take note of zero error. Micrometer Screw Gauge: Total the values of the main scale (1mm) and circular scale readings (0.01mm) to obtain the correct reading. Take note of zero error.

Measurement of Time: Time can be measured with a pendulum, clock or stopwatch.

1.) The time taken for 1 complete oscillation is called the period.

2.) The number of complete oscillations per second is called the frequency.

3.) The period increases with the length of the pendulum.

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Kinematics

Types of Quantities Scalar Quantities are fully described by a magnitude only.

Vector Quantities are quantities described by a magnitude and direction.

Displacement: The distance measured along a straight line in a stated direction with respect to the original point (vector).

Velocity: Rate of change of displacement Displacement (m)Velocity

Time Taken (m/s)

Acceleration: Rate of change of velocity Note: Negative Acceleration = Retardation

Final Velocity Initial VelocityAcceleration

Time Taken (m/s)

Distance (m)

Displacement – Time Graphs (xt Graphs)

3.) Used to show displacement over time. 4.) Horizontal line: Body at rest. 5.) Straight line with positive gradient: Uniform

Velocity. 6.) Straight line with negative gradient: Uniform

velocity in the opposite direction. 7.) Curve: Non – uniform velocity. 8.) The gradient of the tangent of this graph gives the

instantaneous velocity of the object.

Velocity – Time Graphs (vt Graphs)

1.) Used to show velocity over time. 2.) Such a graph can be used to find:

a. Velocity b. Acceleration: Gradient c. Distance travelled: Area under the

graph.

Acceleration of Free – Fall

2. The acceleration of free-fall near the surface of the Earth is constant and is approximately 10m/s2. It is derived from the gravitational force felt by objects near the Earth surface and independent of the mass of any object.

3. Speed of a free-falling body (experiencing no other forces other than gravity) increases by 10m/s every second or when the body is thrown up, it decreases by 10m/s every second.

4. The higher the speed of an object, the greater the air resistance.

5. Terminal Velocity: When an object is moving at constant velocity, acceleration is 0.

6. As an object falls, it picks up speed, increasing air resistance. Eventually, air resistance becomes large enough to balance the force of gravity where the acceleration of the object is 0, reaching constant velocity.

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Forces

Newton’s 3 Law of Motion

Law of Inertia F = maEvery action has an equal and

opposite reaction

Force Is a push or a pull. SI unit: Newton (N)

Effects of Forces on Motion

How reluctant an object is to change. The greater the mass the more reluctant it is.

An object at rest will remain at rest and an object at motion will remain at a constant speed with an absence of a resultant force.

Resultant Force acting on an object = Product of mass and acceleration of object.

Forces always occur in pairs

Action / reaction forces act on different bodies.

Balanced / Unbalanced Forces

When forces are balanced, there is no resultant force, thus no change will occur to the object

When forces are unbalanced, there is a resultant force, thus object will move towards the direction with greater force

Friction

1. It is the net force that slows down moving objects.

2. Acts in the opposite direction of motion of object.

Static Friction: Related to objects which are not moving. Amount of force applied = amount of friction.

Moving Friction: Applied force does not affect friction. It can be affected by surface / sudden mass change

Factors affecting the amount of friction:

1. Material / texture in contact

2. Proportional to force pressing surface

3. Independent on area of

contact.

Advantages: Walking / Brakes / object to remain slanted

Disadvantages: Reduction in efficiency of machinery / energy wasted as heat.

Methods to reduce friction: Lubricants, ball / roller bearings, moving parts made smoother.

Terminal Velocity

1. The greater the velocity of an object, the higher the air resistance. 2. Definition: The constant maximum velocity reached by a body falling through the atmosphere under the

attraction of gravity. 3. When an object reaches terminal velocity, the force of gravity and air resistance are balanced, the object falls

at a constant speed and doesn’t accelerate. 4. Factors affected: Size, surface area, weight and nature of medium where object is flying. 5. NOTE: If an object is falling through a vacuum, there would be no air resistance, thus acceleration is due to

gravity alone.

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Mass, Weight, Density

Mass Weight Density

Definition Mass is the quantity of matter contained in an object.

Weight is the attractive force exerted on an object due to gravity.

Density of a substance is defined as its mass per unit volume.

SI unit Kilogram (kg) Newton (N) kg/m3 or g/cm3

Equation W mg

W: Weight of object (N) m: Mass of object (kg) g: Gravitational Acceleration in m/s

2



Turning Effects of Forces (Moments)

Chapter 5.1: Definitions

1. The moment of a force is the turning effect of a force, or the ability of the force to make something turn.

2. Moment of a force (M) about a point O is the product of the force (F) and the perpendicular distance (D) from the point to the line of action of the force.

3. SI unit: Newton (N) 4. Moments can be clockwise or anticlockwise.

5. The turning effect of a force depends on: a. Location of applied force b. Perpendicular distance between the point of

application of the force and the pivot.

Chapter 5.2: Principle of Moments The principle of moments state that:

6. When the clockwise moment is not equal to the anticlockwise moment, there is a resultant moment. The

When a body is in equilibrium, the sum of clockwise

moments about the balanced point is equal to the sum

of anticlockwise moments about the same point

(pivot).

Total clockwise moment = Total anticlockwise moment.

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object will rotate in the direction of resultant moment. 7. Therefore, if there is no resultant moment, the object is

balanced!

Chapter 5.3: Centre of Gravity (c.g.)

8. Definition: The centre of gravity (CG) of a body is an

imaginary point where the whole weight of the body

seems to act in any orientation.

a. The CG of a regular object is at the centre.

b. The CG of an irregular object is determined using a

plumb line.

9. If a body is hanging freely at rest, its centre of gravity is

always vertically below the pivot, thus the plumb line

method works. It can only be used for flat, irregular objects.

Chapter 5.4: Stability

10. Stability is a measure of the body’s ability to maintain its

original position.

11. There are 3 types of stability:

Stability Type Effect Explanation

Stable Equilibrium

Object will return into original position after slight disturbance

Weight will generate an anticlockwise moment by bringing the cone back to its original position (done by the restoring moment). These types of objects usually have low CG and big/heavier bases.

Unstable Equilibrium

Object will topple/fall after slight disturbance

The weight of the cone will generate a clockwise moment outside the base area of the cone, thus there is a resultant moment and the object will fall.

Neutral Equilibrium

Object remains in new position after slight disturbance

The centre of gravity neither rises nor falls, it remains at the same level. The lines of action of the 2 forces always concide and there is no moment provided by weight to turn the cone.

12. Ways to improve stability of an object:

a. Lowering the CG (A lower CG will allow the line of action to act within the base area of an object)

b. Area of its base should be as wide as possible (allow line of action to act within base area)

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Energy, Work, Power

Work Energy Power

Definition Work done on an object is when a constant force is applied on the object producing a distance moving in the direction of the force.

Energy is the capacity to do work. There are many different types of energy like translational, rotational and vibrational kinetic energy.

Power is defined as the rate of doing work (Rate of energy transfer / conversion)

SI unit Joule (J) Joule (J) Watt (W)

Definition of SI unit

One joule of work is done when a force of one Newton moves through a distance of one metre in the direction of the force.

One joule of work is done when an object with 1kg moves at 1m/s.

One watt is produced when 1 joule of work is done for 1 second.

Equation W FS

W: Work done by constant force (J) F: Constant Force (Newton) S: Displacement of force

21. . :

2K E mv

K.E: Kinetic Energy, m = mass (kg) v = velocity (m/s)

. . :P E mgh

m = mass (kg), g = Gravity Field Strength, h = height of object (m)

or W EP

t

P: Power (W) W: Work done (J) E: Energy (J) t: Time taken (seconds)

Other Info. Work is done on an object only when the force applied on it produces motion.

The principle of conservation of energy states that energy cannot be created or destroyed, but can only change from one form to another.

Efficiency

Useful energy output= 100%

Total energy input



Pressure

Pressure in a solid Pressure in a liquid Pressure in a gas

Definition Pressure is the force acting normal or perpendicularly per unit area.

SI unit Pascal (Pa) or N/m2

Equation ForcePressure =

Area

Pressure = h g h: Depth of the liquid (m) p: Density of liquid (kg/m3) g: Gravitational field strength

The air surrounding us exerts a pressure in all directions which is about 105 Pa.

Other Info. This formula can only be used for solids.

1. A liquid exerts pressure because of its weight.

2. Liquid pressure acts equally in all directions. This is because particles of the water can flow and wrap around the object.

Hydraulics Systems Purpose: Increase the output force

from an input force. However the height which the object can be increased is reduced.

Properties used: Liquids are incompressible and if pressure is applied to trapped liquid, it is transmitted to all parts of the liquid.

1. A barometer is used to measure pressure. It consists of an inverted tube in a dish of mercury. The space above the mercury in the tube is vacuum.

2. Liquid mercury is used as its density is very high and a shorter barometer can be used to show atmospheric pressure.

3. An object can be bent/sucked in due to the production of vacuum and due to the difference in pressure; the atmospheric pressure will press on the object.

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Thermal Physics: Chapter 8

Temperature

Temperature It is a measure of the degree of hotness of a body. Physical Properties :

1. Expansion of column of liquid in capillary tube

2. Voltage of thermocouple 3. Expansion of a bimetallic strip

Desirable Features

1. Easy to read scale 2. Safe 3. Sensitive to temperature

changes 4. Wide range of temperature

Measured using a thermometer Temperature Scale

The Celsius Scale Ice Point: Temperature of pure melting ice at standard atmospheric pressure (0

oC).

Steam Point: Temperature where boiling water changes to steam at standard atmospheric pressure.

The Kelvin Scale Zero: Absolute Zero (where object has nothing in the body) Unit: Kelvin (K).

( ) 273K C K

1oC increase = 1 K increase.

General Equation

Measured Physical Property

Total Range of Physical Property

Types of Thermometers Clinical Thermometer, Liquid in Glass Thermometer, Thermocouple

Difference between Mercury / Alcohol thermometer

Mercury Alcohol

Uniform Expansion

Yes No (Out of Range)

Stick to Glass No (visible meniscus)

Yes (Transparent)

Reaction to temp. changes

Quick Slow

Range Measure Higher Temp.

Measure lower temp.

Cost Expensive Cheap

Poisonous Yes No

Thermocouple

1. Consists of 2 wires of different materials joined together to form 2 junctions.

2. A voltage is produced when the junctions are at different temperatures. It increases as the temperature increases.

3. Suitable for measuring wide temperature differences, which vary rapidly due to its quick response and temperature at a point as wire junctions are small.

4. Can be connected in series to increase sensitivity.

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Kinetic Model of Matter

Molecular Model of the 3 states of matter

Solid Liquid Gas

Forces between Molecules Balanced, strong As strong as solid Negligible

Distance between molecules

Small, arranged in regular pattern

Slightly further apart, no pattern

Far apart, mainly empty space

Motion of molecules Vibrate about fixed positions

Vibrate to and fro Move randomly with high speed, colliding with one another and walls.

Compression No No Yes

When heated Molecules gain energy and vibrate more, separation between molecules increase slightly

Molecules vibrate and move about more vigorously, separation between molecules increase slightly

Move at higher speed, collision with one another and walls increases. Expands the most.

The kinetic theory of matter states that all matter is made up of large number of tiny atoms or molecules which are in continuous motion.

Diffusion

It is the spreading of molecules on their own accord without any external aid.

Occurs in liquids and gases Occurs as particles are in random motion Depends on temperature and density

(concentration) of fluid. The lower the density, the more space for particles to move into.

Pressure exerted by a gas

When a gas molecule hit the walls of the container, it exerts a force on the container.

Pressure increases when: 1. Volume of container decreases at constant

temperature 2. Temperature of gas increases at constant volume 3. Number of gas molecules increase, total pressure

exerted increases.

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Transfer of Thermal Energy

Transfer of Thermal Energy: When 2 objects are placed in contact with one another, their temperature eventually becomes the same, known as thermal equilibrium. Note: Heat

travels from a region of high temperature to low temperature.

Conduction

Heat is transmitted layer by layer through a medium from

one particle to another.

Collision between

neighbouring particles

Flow of free electrons

(conductors only)

Convection

Process where heat is transmitted from one

place to another by the movement of heated

particles of a gas/liquid.

Mechanism: Change in Density.

Radiation

A method of heat transfer wher ethe source of heat transmit energy through electromagnetic waves. A medium is not required.

Factors: Temperature of object, surface of object, surface area of object. Good emitters are also good absorbers of radiation.

Conduction: 1. Collisions between neighbouring particles.

a. Particles nearer to heat source gain energy and vibrate faster. b. Particles collide into less energetic neighbouring particles which gains kinetic energy. c. The less energetic particles vibrate faster, collides into other particles. d. Process continues layer by layer to spread the heat to cooler parts.

2. Flow of free electrons (conductors only) a. Electrons near heat source gain energy, move faster. b. Free electrons can move between the particles and collide with other electrons, allowing the less

energetic electrons to gain energy and move faster. c. Process continues to spread the heat to cooler parts.

Convection 3. Fluid nearer to heat source gains heat and expands. 4. Expansion causes decrease in density for the fluid nearer to heat source, causing it to rise. 5. The hotter fluid rises over the cooler fluid while the cooler fluid rushes in to take the space. 6. The process continues and a convection current is formed. 7. Convection is faster than conduction as there is bulk movement (all the molecules get hot and move up,

thus it is faster than conduction.

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Light, Waves and Sound: Chapter 12

Light

Regular Reflection

Occurs at smooth surfaces. Parallel light rays incident on the surface are reflected in one direction only (all rays have the same incident/ reflected ray). The normals of all points of incidence are equal. Characteristics of image formed by plane mirror

Same size as object Laterally inverted Upright Virtual (not real, cannot be captured on screen) The distance of the image from the mirror = distance of

object from the mirror.

Applications of Mirrors: Optical Testing (Mirrors can make letters appear further

away, saving space) Blind Corners (for drivers) Periscopes

Light

Speed: 3 x 108 Path it travels is a light ray. Can be parallel beam, converging beam or diverging beam.

Objects which give out light are luminous objects, those which doesn’t are non-luminous.

Chapter 12.1: Reflection of light

Important terms: Incident Ray: Light ray hitting the reflecting

surface. Reflected Ray: Light ray reflected from the

reflecting surface. Normal: The perpendicular to the reflecting

surface at the point of incidence. Angle of incidence (i): The angle between the

incident ray and the normal. Angle of reflection (r): The angle between the

reflected ray and the normal.

Laws of Reflection:

The incident ray, reflected ray and the normal of the reflecting surface lie on the same plane. Angle of incidence = Angle of Reflection

Diffuse Reflection

Occurs at rough surfaces (sandpaper, burnt boots). Parallel light rays incident on the surface is reflected in all directions. The normals are not parallel.

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Chapter 12.2: Refraction of light

Refraction is the bending effect of light as it passes through another medium of different density.

Refraction occurs as the speed of light varies in different media. Conditions for refraction:

The light must pass from one optical medium to another of different optical density

Angle of incidence more than 0°. Laws of Reflection:

The incident ray, the normal and the refracted ray all lie on the same plane.

For 2 particular transparent media, the ratio of the sine of the angle of incidence to the sine of the angle

of refraction is a constant. Constantsin

sin

r

i

When light travels from a less dense medium to a denser medium, the ray of light moves towards the normal. Likewise, when light travels from a denser to a less dense medium, the ray of light moves away from the normal.

When light enter a medium perpendicularly, regardless of its density, no deviation of the ray is observed.

Refractive Index

The value of the constant ratio sin i/sin r for a ray passing from air/vacuum to a give medium is known as the refractive index of the medium.

The greater the value of the refractive index, the greater the bending of light, the more the light is slowed down and the denser the medium is.

Medium Refractive Index,

Diamond 2.5

Glass 1.4 – 1.9

Water 1.33

Air 1.00

When angle of incidence < Critical Angle: Normal Refraction

When angle of incidence = Critical Angle: Travels perpendicular to the surface (90°)

As i is made bigger, the refracted ray gets closer and closer to the surface of the glass.

Can be found by taking1 1

sincn

When angle of incidence > Critical Angle: Total Internal Reflection.

Refracted ray cannot escape from the glass. Refraction cannot happen and light is reflected at the glass / air boundary.

Total Internal Reflection occurs when a ray of light which is incident on the boundary between 2 medium is totally reflected back into the first.

Applications of Total Internal Reflection: Periscope and Binoculars Optical Fibres

Daily Phenomena of Reflection

Swimming pool appears shallower than it actually is. To find the refractive index of the medium, take

.

Bent objects in liquids. To find refractive index use same

formula as above.

Dispersion of white light. This is due to different colours travelling different speeds in glass.

Red deviates (slows down) the least. Violet deviates (slows down) the most.

http://www.gcsescience.com/pwav18.htm

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Chapter 12.3: Converging Lens

Features of a converging lens Optical Centre (C): The midway point between the lens surface on the principal axis Principal axis: The line passing symmetrically through the optical centre of the lens Principal focus (F): Point on the principal axis where rays of light converge after passing through the lens Focal length (f): Distance between the optical centre, C and the principal focus F. Focal plane: Plane which passes through F and P. It is perpendicular to principal axis.

As light rays can pass through the lens from both sides, each lens has 2 principal foci and 1 focal length on

each side of the lens.

A thicker lens has a shorter focal length and bends light rays to a greater extent whereas a thinner lens has a longer focal length and bends light rays to a shorter extent.

Linear magnification, m, is defined as Object ofHeight

Image ofHeight or

DistanceObject

Distance Image

�

.

Action of a thin converging lens on a

parallel beam of light parallel to the

principal axis.

Action of a thin converging lens on a

parallel beam of light NOT parallel to

the principal axis.

Object distance

Properties of Image

Image Distance

Uses

Object distance is

infinity (parallel rays)

Inverted, real, diminished

(smaller)

Focal length opposite of

lens

Object lens of a telescope

Object distance is

more than 2 focal lengths

Between 1 and 2 focal

length opposite lens

Camera, eyes

Object distance is 2 focal length

Inverted, real, same size

2 focal length opposite lens

Photocopier (equal sized

copy)

Object distance

between 1 and 2 focal length

Inverted, real, magnified

More than 2 focal length

opposite lens

Projector, photograph

enlarger

Object distance is 1 focal length Upright,

magnified, virtual

Infinity, same side of lens

Spotlight

Object distance is less

than 1 focal length

Image behind object, same side of lens

Magnifying glass

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Waves

A wave is a phenomenon in which energy is transferred through vibrations.

Waves Properties of waves: 1. The source of any wave is a vibration or oscillation. 2. Waves transfer energy from 1 point to another. 3. In waves, energy is transferred without the medium being transferred.

1. Transverse waves are waves that travel perpendicular to the direction of motion.

2. Examples of such waves include rope waves and water waves.

3. The crest is the highest points of the wave whereas the trough is the lowest points of the wave.

1. Longitudinal Waves are waves that travel parallel to the direction of motion.

2. Examples are sound wave and pressure waves. 3. They form compressions and rarefactions. 4. Compressions are region where the air particles

are close together, creating high pressure. 5. Rarefactions are areas where the air particles are

far apart, creating low pressure.

Wave Terms

1. A wavelength is the shortest distance between any 2

corresponding points in a wave. SI unit: metre.

2. Symbol: 3. Amplitude is the maximum displacement from the rest

or centre position (high of a crest or depth of a trough). SI unit: metre.

1. Wavefront: This is an imaginary line on a live that joints all points that are in the same phase.

2. It is usually drawn by joining the wave crests.

1. Frequency (f):It is the number of complete waves per second. In other words, the number of occurrences within a given time period.

2. When there is a higher frequency, more waves are produced in 1 second, thus the period will be shorter.

3. SI unit: Hertz (Hz).

4. Period (T): This is the time taken for 1 point on

the wave to complete 1 oscillation. In order words, it is the time taken to produce 1 wave.

5. The SI Unit is seconds (s).

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1. Wavespeed: It is the distance of the wave moved in 1 second in the medium. It is dependent of the medium itself. For example, for sound, the wavespeed is always the same unless the medium is changed from solid to liquid.

2. Real life example: If the crest of an ocean

wave moves a distance of 20 meters in 10 seconds, then the speed of the ocean wave is 2 m/s. On the other hand, if the crest of an ocean wave moves a distance of 25 meters in 10 seconds (the same amount of time), then the speed of this ocean wave is 2.5 m/s. The faster wave travels a greater distance in the same amount of time.

3. It is measured in metre per second.

Chapter 13.6: Graphical Representation of Waves

A displacement-position graph shows how high or low a wave is at a particular position.

A displacement-time graph shows the displacement of a single particle at a particular position o the particle as time changes

Both graphs can be used to represent a longitudinal or transverse wave.

Chapter 13.7: Refraction and Reflection of Waves

1 It only changes if the source of the waves is changed (e.g. vibrating faster) 2 This is due to the wave having more energy in deep water (more space)

1.) When water waves get reflected, the only thing that changes is the direction. The wavelength, frequency and speed remains the same throughout. Sponges are used to absorb the reflections of the water waves.

2.) When water waves get refracted (move from deep to shallow water), the speed and the wavelength changes. The frequency of the wave does not change1.

Deep water Shallow water

Faster speed2

Slower speed

Longer wavelength

Shorter wavelength

Similar Frequency

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Electromagnetic Spectrum

1.) Electromagnetic waves are transverse waves. They are electric and magnetic fields that oscillate at 90° to each other.

2.) They transfer energy from one place to another.

3.) They can travel through vacuum (do not require any medium to travel)

4.) They travel at 3.0 x 108 per second in vacuum. They will slow down when travelling through water or glass.

5.) The wave equation is applicable here too.

6.) They obey the laws of reflection and refraction.

7.) They carry no electric charge (they are neither positively or negatively charged)

8.) Their frequencies do not change when travelling from one medium to another. Only their speeds and wavelength will change.

Uses of Electromagnetic Waves

Wave Uses Dangers

Radio Waves Radio transmitters Radar Television

None

Microwaves Microwave ovens Communication system

Internal heating of body tissue

Infra-red Thermal imaging Remote controls

Burns skin

Light Optic fibres Seeing!

Strong light causes damage to vision.

Ultra-violet Washing powder (whiter than

white) Security marking

Skin cancer and blindness

X rays Taking images of the skeleton Mutations in cells and severe burns to the skin.

Gamma Rays Cancer treatment Sterilisation of equipment

Cancers and cell mutation

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Sound

Sound is a form of energy. The energy is passed from 1 point to another as a wave.

Sound Sound is an example of longitudinal wave. Sound is produced by vibrating sources placed in a medium (air). It travels in air through a series of compressions or rarefactions.

Compressions: Air molecules are close together, forms high pressure. Rarefactions: Air molecules are far apart, forms low pressure.

2.) Speed of sound differs in different medium. Air: 330 - 340m/s Water: 1500m/s Glass:5000m/s

3.) Speed of sound differs because:

Differences in strength of interatomic forces Closeness of atoms in the 3 states Temperature

4.) The Wave Equation can also be used to find the speed of

sound (refer to page 11)

5.) The speed of sound is solids like metals are so fast that we can assume/ignore the time it takes to travel a distance.

Echoes

6.) Echoes refer to the repetition of a sound resulting from reflection of the sound waves.

7.) Echoes are formed when a sound is reflected off a hard and flat surface.

8.) Reverberation occurs when the surface is too close, causing any reflected sound to follow closely behind the direct sound and prolonging the original sound.

Ultrasound

9.) The range of frequencies which a person can hear is known as the range of audibility.

Human: Between 20 Hz and 20 kHz1 Dog: <20 kHz Bats: Between 10 kHz and 120 kHz.

10.) Ultrasound is the sounds with frequencies above

the upper limit of the human range of audibility. Its small wavelength means less diffraction and the echo formed is more precise in direction.

11.) Applications for ultrasound include: Determining depth of seabed Locating sunken ships / shoals of fish Cleaning small dirt from jewellery. Quality control (checking for cracks) in concrete Medical applications (development of foetus)

Loudness and Pitch

12.) Loudness is a factor distinguishing between various sounds.

The larger the amplitude of vibration, the louder the sound

Sound is measured by decibels (dB).

13.) Pitch is a factor distinguishing various sounds The higher the frequency of a note, the higher

the pitch Pitch is measured in hertz (Hz).

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