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Definitions |
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Intensity (3)
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power/area
IαAmplitude2
Iα1/r2
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What can microwaves be used for in communication?
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Amplitude
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MAXIMUM DISPLACEMENT FROM EQM. POSITION (A)
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Luminous
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Objects that produce visible light.
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Medium
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The carrier of a wave
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Wave
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- traveling disturbance that carries energy through medium- wave speed only depends on medium
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Polarization
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-the orientation of oscillations in the plane perpendicular to a transversal wave’s direction of speed.
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Constructive Interference
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Increases amplitude when waves interact.
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Cornea
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A transparent membrane that protects the eye and refracts light.
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X-Rays
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High energy electromagnet waves that are between ultraviolet light and gamma rays in the electromagnetic spectrum.
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Two forms of wave?
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Electromagnetic and Magnetic
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Antinode
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POINT AT WHICH A STANDING WAVE OSCILLATES WITH MAXIMUM AMPLITUDE
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Malus' law
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INTENSITY OF PLANE POLARISED LIGHT PASSING THROUGH A POLARISING FILTER IS PROPORTIONAL TO cos^2 ANGLE OF ROTATION OF THE FILTER RELATIVE TO THE PLANE OF POLARISATION.
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What occurs when two waves pass through the same region of space at the same time?
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Interference.
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what does transparnet mean?
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it allows light thought
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Scattering
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The release of light energy by particles of matter that have absorbed energy.
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Electromagnetic Spectrum
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The entire range of electromagnetic waves.
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Translucent
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Matter that transmits light but also scatters the light as it passes through matter. Wx paper is an example of translucent matter.
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Resonance
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AN objecting vibrationg at its natural frequency can cause another object with the same natural frequency to start vibrating
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Define wavelength.
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Wavelength (lamda a Greek letter 'l') is the shortest distance between two particles that are oscillating in phase. (Distance between two crests on a displacement/distance graph). It is measured in metres (m)
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Transverse
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The motion of particles in the wave are perpendicular to it (sin)
i.e. earthquakes
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Frequency
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NUMBER OF VIBRATIONS PER SECOND OF A PARTICULAR PARTICLE - OR - NUMBER OF WAVES PASSING A FIXED POINT PER SECOND (f IN Hz)
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Standing Waves
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TWO PROGRESSIVE WAVES OF THE SAME FREQUENCY, VELOCITY AND SIMILAR AMPLITUDE PASS OVER ONE ANOTHER IN OPPOSITE DIRECTIONS.
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What is an antinodes?
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Points of constructive interference (max amplitude)
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Doppler Effect
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-the phenomenon of the change in frequency that arises from the relative motion between a source and observer.
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What can microwaves be used for in communication?
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mobiles and satellite tv
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Displacement
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Distance of a Particle on the wave from its equilibrium position.
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Progressive Waves
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Transfer energy from one point to another
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diffraction
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the bending of waves, esp. sound and light waves, around obstacles in their path.
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conduction
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the transfer of heat between two parts of a stationary system, caused by a temperature difference between the parts
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Law of Reflection
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During reflection, the angle of incidence is equil to the angle ofo reflection
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Propagate
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The name given to the traveling of waves
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What is frequency?
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Frequency (f) is the number of oscillations per second. It cannot be read directly off a graph. You need to find (T) from the displacement/time graph and then find its reciprocal (f =1/T)
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What are analogue signals?
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Analogue signals contain all the information as a continuously varying wave.
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Periodic Motion
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If an object oscillates back and forth over the same distance and each cycle taking the same amount of time.
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Period
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TIME TAKEN FOR A PARTICLE TO MAKE ONE COMPLETE OSCILLATION - OR - TIME IT TAKES FOR ON COMPLETE WAVE TO PASS A FIXED POINT (T)
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What type of wave has particles that move in the same direction as (parallel to) the motion of the wave?
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Longitudinal Waves
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How do you fine speed?
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speed = frequency x wavelength
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What can infrared radiation be used for in communication?
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It is also used for television remote controls and in optical fibre communications.
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Loudness
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How loud or soft a sound is perceived to be.
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Pitch
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How log or how high you perceive a sound to be.
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Stationary Waves - Definition
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Have energy 'stored' between two points
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reflection
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the act of reflecting or the state of being reflected.
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Resonant Frequency
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The frequency at which a standing wave will occur
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Electromagentic Wave
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Waves that do not need a physical medium to propagate
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Physical Medium
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Something that you can touch, like air or water
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Define a longitudinal wave.
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The vibrations in a longitudinal wave are parallel to the direction in which the energy is travelling. Eg. sound.
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Fundamental Mode of Vibration
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THE LOWEST FREQUENCY IN A HARMONIC SERIES WHERE A STATIONARY WAVE IS FORMED.
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From a LESS dense medium to MORE dense, which pulse (transmitted or reflected) are on the opposite side (out of phase) as the incident phase?
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The reflected pulse.
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Diffraction and Interference
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- when there are two barriers placed near each other the two diffracted waves will interface with each other, causing a pattern to form.
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Convex Lens
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A lens that is thicker in the middle than at the edges.
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Interference
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The creation of a new wave when two or more waves interact with each other
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What are digital signals?
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Digital signals are a series of pulses - either high or low - on or off - sometimes expressed as binary code 1s and 0s.
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Is the wavelength the greatest in the least dense medium or the most dense medium?
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The least dense medium.
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What are the movements in a transverse wave?
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The movements are sideways or up and down in a transverse wave.
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Definition of a Wave
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The movement of energy from one point to another
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Out-of-Phase points
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Any two points on a wave that are not in-phase
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What are different types of transverse waves?
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Water waves, gamma, x-ray, ultra violet, light, infra red, microwaves, radio waves
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What sort of wave is a radio wave? Longitudinal wave or transverse wave?
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A radio wave is a transverse wave.
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At what speed does electromagnetic waves travel at through air?
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At a speed of 300 million m/s through air.
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Define a Longitudinal Wave. Give an example.
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The particles in the medium oscillate about their positions parallel to the direction of motion of the wave.
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Define a Transverse Wave. Give an example
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The particles in the medium oscillate about their positions perpendicular to the direction of motion of the wave.
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From a MORE dense medium to LESS dense, how does the velocity of the transmitted pulse compare to the reflected pulse?
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The transmitted pulse is FASTER than the reflected pulse.
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What sort of wave is a light wave? Longitudinal wave or transverse wave?
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A light wave is a transverse wave.
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What is the period of a wave?
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Period (T) is the time taken for one complete oscillation of a particle in the wave. (Distance between two crests on a displacement/time graph). It is measured in seconds (s).
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What sort of wave is a sound wave? Longitudinal wave or transverse wave?
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A sound wave is a longitudinal wave.
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