Physics: Waves, Electricity, Magnetism, and Mechanics

Comprehensive vocabulary flashcards covering wave mechanics, sound, electromagnetic radiation, magnetism, electrostatics, electric circuits, vectors and scalars, and one-dimensional kinematics based on the provided physics lecture study guides.

Pulse

A single disturbance in a medium.

Transverse pulse

A pulse whose particles vibrate perpendicular to the direction of the pulse's motion.

Longitudinal pulse

A pulse whose particles vibrate parallel to the direction of the pulse's motion.

Superposition

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

Constructive interference

A phenomenon where the crest of one wave overlaps with the crest of another wave to produce a wave of increased amplitude.

Destructive interference

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

Interference

A phenomenon where similar waves with a regular phase relationship pass through the same region at the same time.

Amplitude

The maximum displacement of a particle from its equilibrium position.

Transverse wave

A wave in which the disturbance is at right angles to the direction of propagation (motion) of the wave.

Crest

The highest point (peak) on a (sine) wave.

Trough

The lowest point (valley) on a (sine) wave.

Frequency

The number of cycles/vibrations per unit time.

Period

The time taken for one complete cycle of an oscillation or vibration.

Point in phase

Two points on a wave that move exactly in the same way at the same time, e.g. two crests or two troughs.

Wavelength

The distance between two successive points in phase.

Wave speed

The distance travelled by a point on a wave per unit time.

Longitudinal wave

A wave in which the disturbance/displacement (from the position of rest) is parallel to the direction of propagation (motion) of the wave.

Compression

The region of high pressure in a longitudinal wave.

Rarefaction

The region of low pressure in a longitudinal wave.

Loudness

A subjective term describing the strength of the ear's perception of a sound. Loudness is directly proportional to amplitude.

Pitch

The effect produced in the ear due to the sound of a particular frequency. Pitch is directly proportional to frequency.

Ultrasound

Ultrasonic vibrations having frequencies higher than $20\,000\,\text{Hz}$.

Photons

Packets of energy of which light is composed.

Electromagnetic waves

Waves that originate from oscillating electric charges, propagate as electric and magnetic fields perpendicular to each other, can travel through a vacuum, and have a speed of $3 \times 10^8\,\text{m}\cdot\text{s}^{-1}$.

Magnetic field

A region in space where another magnet or ferromagnetic material will experience a force.

Ferromagnetic materials

Materials such as iron, nickel, cobalt, and their alloys that are strongly attracted by magnets and magnetised easily.

Electrostatics

The study of charges at rest.

Elementary charge

An indivisible unit of charge, i.e. $1{,}6 \times 10^{-19}\,\text{C}$.

Polarisation (of charge)

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

Quantization (of charge)

Division of charge in smaller units.

Principle of conservation of charge

Charge cannot be created or destroyed. It can only be transferred from one object to another.

Principle of charge quantization

Every stable and independent object has a charge that is an integer multiple of the elementary charge.

Triboelectric charging (Triboelectric effect)

A type of contact electrification in which certain materials become electrically charged after they come into contact with another different material and are then separated (such as through rubbing). The polarity and strength of the charges produced differ according to the materials.

Electric current

The rate of flow of charge: $I = \frac{Q}{\Delta t}$.

Ampere (A)

The unit of measurement of electric current. The current is one ampere when a charge of one coulomb passes a given point in a conductor in one second.

Coulomb (C)

The unit of measurement of electric charge.

Emf

The potential difference (voltage) measured across the terminals of a battery when no charge flows through the battery.

Potential difference

The potential difference between the ends of a conductor is equal to the energy transferred (from electrical to other forms of energy) per unit electric charge flowing through it: $V = \frac{W}{Q}$.

Volt (V)

The unit of measurement of potential difference.

Resistance

The ratio of the potential difference across a resistor to the current in the resistor: $R = \frac{V}{I}$.

Ohm ($\Omega$)

Unit of measurement of resistance. One ohm is one volt per ampere.

Voltmeter

The instrument used to measure potential difference. Connected in parallel and has a very high resistance.

Ammeter

The instrument used to measure electric current. Connected in series and has a very low resistance.

Vector

A physical quantity with magnitude and direction.

Scalar

A physical quantity with magnitude only.

Displacement

The change in position of an object from a point of reference (length and direction of the straight line drawn from the beginning to the endpoint).

Distance

The total path length travelled by an object.

Force

Any influence which tends to change the motion of an object.

Mass

The amount of matter in an object.

Resultant

A single vector having the same effect than two or more vectors acting together.

Weight

The force of attraction of the earth on an object.

Tail-to-head method

A method of vector addition where each subsequent vector is drawn with its tail at the head of the preceding one, and the resultant is drawn from the tail of the first vector to the head of the last vector.

Frame of reference

A set of axes from which position or motion can be measured.

Position

The place occupied by an object - a measurement of a location with reference to an origin.

Motion in one dimension

Motion of an object in one plane only and in a straight line.

Average speed

The total distance travelled per time.

Average velocity

The total displacement per time.

Acceleration

The rate of change of velocity.

Instantaneous speed

The speed at a specific moment (magnitude of instantaneous velocity).

Instantaneous velocity

The velocity at a specific moment (displacement divided by an infinitesimal time interval).

Speed

The rate of change of distance.

Velocity

The rate of change of position.