Physics Paper 1

Define a pulse

A single disturbance in a medium

Define a transverse pulse

A pulse in which the particles of the medium move at right angles to the direction of motion of the pulse.

Define amplitude

the maximum disturbance of a particle from its rest (equilibrium) position

Define the principle of superposition

the algebraic sum of the amplitudes of two pulses that occupy the same space at the same time.

Define constructive interference

the phenomenon where the crest of one pulse overlaps with the crest of another to produce a pulse of increased amplitude

Define destructive interference

the phenomenon where the crest of one pulse overlaps with the trough of another, resulting in a pulse of reduced amplitude.

Apply the principle of superposition to pulses to explain

Using diagrams, how two pulses that reach thee same point in the same medium superpose constructively and destructively and then continue in the original direction of motion.

Define a transverse wave

Wave in which the particles of the medium vibrate at right angles to the direction of motion of the wave.

Is a succession of transverse pulses.

Define the term “Wavelength”

The distance between two successive points in phase.

Define the term “frequency”

The number of wave pulses per second

Define the term “period”

The time taken for one complete wave pulse

Define the term “Amplitude”

The maximum displacement of a particle from its equilibrium position

Define the term “Crest”

Highest point (peak) on a wave

Define the term “Trough”

Lowest point on a wave

Explain the wave concepts in phase and out of phase

In phase - Two points in phase are separated by a whole number (1; 2; 3 ; …) multiple of complete wavelengths

Out of phase - Points that are not separated by a whole number multiple of complete wavelengths

Define Wave speed

the distance travelled by a point on a wave per unit time

Define a Longitudinal wave

A wave in which the particles of the medium vibrate parallel to the direction of motion of the wave

Define the wavelength

the distance between two successive points in phase

Define Amplitude

the maximum displacement of a particle from its equilibrium position

Define a compression

a region of high pressure in a longitudinal wave (crest)

Define a rarefaction

a region of low pressure in a longitudinal wave (trough)

Define frequency

the number of wave pulses per second

Define period

the time taken for one complete wave pulse

What type of wave is a sound wave

longitudinal wave

Define pitch

the effect produced in the ear due to the sound of a particular frequency

(the sound of frequency, directly proportional)

Define Loudness

the amplitude of a sound wave and the sensitivity of the human ear

(loudness directly proportional to them)

Define pure note

Regular wave pattern and single frequency

Define noise

Irregular wave pattern

Define Ultrasound

Sounds above 20 000 Hz but less than 100 000 Hz

Humans are not sensitive to it. They are sensitive to sounds between 20 Hz and 20 000 Hz

Uses of Ultrasound

• Dolphins and bats track their prey using ultrasound

• Ships, for finding shipwrecks and submarines

• Sonars for pregnancy scans

• Treatment for breaking up kidney stones

• Diagnosis and location of blockages in arteries and veins

Explain how an image can be created through Ultrasound

It is based on the fact that when a wave encounters a boundary between two media, part of the wave is reflected, part of the wave is absorbed and part is transmitted

What determines the speed of a wave

Elasticity, Density and Tension of the medium

How are objects charged

• Friction

• Contact

• Induction

Unit of Measurement for charge

Unit : Coulombs (C)

Symbol (Q)

State the principle of conservation of charge

The net charge of an isolated system remains constant during any physical process

State the principle of charge quantization

All charges in the Universe consist of an integer multiple of the charge of one electron

eg 1,6 × 10 to the -19 C

Polarisation

The partial or complete polar seperation of positive and negative electric charge in a system

Define potential difference (volts)(V)(Voltage)

The energy transferred across the ends of conductor per unit electric charge flowing through it. V = W/Q

Define emf

The work done per unit charge by the source (battery). It is equal to the potential difference measured across the terminals of a battery when no charges are flowing in the circuit

Define Terminal Potential Difference

The voltage measured across the terminals of a battery when charges are flowing in the circuit

Define current strength (I)(Current)(Amperes)(C/seconds)

The rate of flow of charge

define one coulomb

the charge transferred in a conductor in one second if the current is one ampere

how are voltmeters and ammeters connected in circuits

voltmeters - parallel

ammeters - series

define resistance

The ratio of the potential difference across a resistor to the current in the resistor

explain resistance

the opposition to the flow of electric charges

define the unit of resistance

one ohm is equal to one volt per ampere

define ohms law

The potential difference over a resistor is directly proportional to the current flowing through the resistor, provided the temperature of the resistor remains constant. Conductors that obey ohm’s law are called ohmic conductors (most metal conductors), while the ones that don’t are called non-ohmic conductors eg filament of a light bulb

Conductors

• Materials that can conduct an electrical current

• Metals, because their valence electrons are delocalised and are therefore free to move around

• Substances that offer little resistance to a flow of charge

Insulators

• Materials that cannot conduct an electric current

• Materials that offer resistance to a flow of charge

• Non-metals like plastic, Teflon, porcelain and rubber

List physical quantities of vectors and scalars

Time, Mass, Weight, force, charge, etc

Define a vector and a scalar quantity

A vector is a physical quantity with magnitude and direction.

A scalar is a physical quantity with magnitude only

Define a resultant

As the single vector having the same effect as two or more vectors together

Describe the concept of a frame of reference

A coordinate system used to represent and measure properties of objects, such as position

Define one-dimensional motion

Motion along a straight line. The object may move forward or backward along this line.

Define position relative to a reference point

Understand that position can be positive or negative

Define distance

The total path length travelled

Know that distance is a scalar quantity

Define displacement

The difference in position in space

Know that displacement is a vector quantity that points from the initial to the final position

Define average speed

Total distance travelled per total time.

Know that average speed is a scalar quantity

Define average velocity

The rate of change of position

Define acceleration

The rate of change of velocity

What is Positive acceleration

An object moving in the positive direction is experiencing an increase in speed and an object moving in the negative direction is experiencing a decrease in speed

What is Negative acceleration

An object moving in the positive direction is experiencing a decrease in speed and an object moving in the negative direction is experiencing an increase in speed

What is Deceleration

An object is experiencing a decrease in speed

Define instantaneous velocity

Rate of change in position ie the displacement divided by a very small time interval or the velocity at a particular time. Instantaneous Velocity is a vector quantity

Define Instantaneous speed

The magnitude of the instantaneous velocity. Instantaneous speed is a scalar quantity

What is Uniform velocity

Motion at constant velocity ie No acceleration

What is Uniform accelerated motion

The velocity of an object changes with the same amount during each time interval

Define gravitational potential energy of an object

the energy it has because of its position in the gravitational field relative to some reference point

Define kinetic energy

the energy an object possesses as a result of its motion

Define Mechanical energy

the sum of the gravitational potential energy and kinetic energy

State the law of the conservation of energy

The total energy of an isolated system remains constant

What is an isolated system

A system that does not interact with its surroundings

ie there is no transfer of energy or mass between the system and the surroundings

State the principle of conservation of mechanical energy

The total mechanical energy in an isolated system / in the absence of dissipative forces

eg friction, remains constant