Waves Flashcards
What is the definition of a pulse?
A single disturbance in a medium
What is the definition of a transverse pulse?
A pulse in which the particles of the medium move at right angles to the direction of motion of the pulse
What is the definition of an amplitude?
The maximum distance of a particle from its rest (equilibrium) position
What is the definition of the principle of superposition?
The algebraic sum of the amplitudes of two pulses that occupy the same space at the same time
What is the definition of constructive interference
The PHENEOMENON where the crest of one pulse overlaps with the crest of another to produce a pulse of increased amplitude
What is the definition of destructive interference?
The PHENOMENON where the crest of one pulse overlaps with the trough of another, resulting in a pulse of reduced amplitude
What is the definition of a transverse wave?
A wave in which the particles of the medium vibrate at right angles to the direction of motion of the wave. A transverse wave is a succession of transverse pulses
What is the definition of wavelength?
The distance between two successive points in phase
What is the definition of frequency
The numberof wave pulses per second
What is the definition of a period
The time taken for one complete wave pulse
What is the definition of amplitude
The maximum displacement of a particle from its equilibrium position
What is the definition of a crest
The highest point (peak) on a wave
What is the definition of a trough?
The lowest point on a wave
Explain the wave concept, “in phase”
Two points in phase are separated by a whole number (1; 2; 3;…) multiple of complete wavelengths
Explain the wave concept, “out of phase”
Points that are not separated by a whole number multiple of complete wavelengths
What is the definition of wave speed
The distance travelled by a point on a wave per unit of time
What is the definition of a longitudinal wave
A wave in which the particles of the medium vibrate parallel to the direction motion of the wave
What is the definition of a compression
A region of high pressure in a longitudinal wave
What is the definition of a rarefaction
A region of low pressure in a longitudinal wave
Explain how sound waves are created
Sound waves are created by vibrations in a medium in the direction of propagation. The vibrations cause a regular variation in pressure in the medium
Describe a sound wave/What type of wave is a sound wave?
A longitudinal wave
What are echoes?
Echoes are reflections of sound waves
How is the pitch of a sound related to the frequency of a sound wave?
Pitch is the effect produced in the ear due to the sound of a particular frequency. Pitch is directly proportional to frequency.
How is the loudness of a sound related to both the amplitude of a sound wave and the sensitivity of the human ear?
Loudness is a subjective term describing the strength of the ear’s perception of a sound. Loudness is directly proportional to amplitude.
How is the quality of sound related to the waveform as it appears to the listener?
Two notes of the same pitch and loudness, played on different instruments do not sound the same because the waveforms are different and therefore differ in quality or tone
What are sounds with frequencies higher than 20kHz up to about 100kHz?
Ultrasound
Explain how an image can be created using ultrasound
When a wave encounters a boundary between two media, part of the wave is reflected, part is absorbed, and part is transmitted.
What are some of the benefits and uses of ultrasound?
Safety, diagnosis, treatment and pregnancy
What are the two methods of explaining the behaviour of electromagnetic radiation?
Some aspects of the behaviour of electromagnetic radiation can best be explained using a wave model and some aspects can be explained using a particle model.
Describe the source of electromagnetic waves
An accelerating charge
How does an electromagnetic wave propagate?
An electromagnetic wave propagates when an electric field oscillating in one plane produces a magnetic field oscillating in a plane at right angles to it, which produces an oscillating electric field, and so on.
What is the constant speed that mutually regenerating fields travel through space?
3×10^8 m.s^-2 as represented by c
What are the properties of electromagnetic waves?
- They originate from accelerating electric charges
- Propagate as electric and magnetic fields that are perpendicular to each other
- Can travel through a vaccuum
- Have a speed of 3×10^8 m.s^-1
What is the definition of a photon?
A packet of energy found in light
Explain the dual nature of electromagnetic radiation
Explain that some aspects of the behaviour of electromagnetic radiation can best be explained
using a wave model and some aspects can best be explained using a particle model.
