Science Physics Unit 1 Year12 Flashcards
Define and give examples of a longitudinal wave
where particles vibrate parallel to the path of propagation e.g. sound
Define and give examples of a transverse wave
where particles vibrates perpendicular to the path of propagation e.g. water ripples , guitar plucking , electromagnetic waves
Define in phase and out phase
in phase is when points on a wave are plotted at the same position of the wave cycle , Out phase is when points on a wave are plotted at a different position of a wave cycle
Define coherence
when two wave sources have identical frequency and waveforms and the phase difference is constant
Define superstition
overlapping of waves e.g. large and small wave ripples
Define stationary waves
two waves moving in opposite directions , having the same amplitude and frequency
Define and explain diffraction grating
light is made up of several different colours , all of them travel in different paths at different frequencies
Explain how to find wave speed
frequency x wavelength
Define amplitude
the maximum extension of oscillation from the equilibrium
Define oscillation
regular repetitive motion of going back and forth
Define resonance and give an example
the storing of energy in oscillation/stationary wave, energy coming from a external source of frequency, strumming a guitar is an example
Define a node in terms of standing/stationary waves
a point of zero vibration
Define a antinode in terms of standing/stationary waves
the point of maximum vibration
Define emission spectra/spectrum
range of frequencies of light emitted by a element
State the equation for refractive index
n = c/v = sin(i)/sin(r)
Explain the difference between analogue and digital signals
analogue uses a range of values to represent information, digital uses 0’s and 1’s binary
What are the properties of different regions of the electromagnetic spectrum related to?
their frequencies and wavelength
State the order of increasing frequency in the electromagnetic spectrum
radio waves, microwaves, infrared, visible light, UV, x-rays, gamma rays
How much is a MHz?
10 x the power of 6 Hertz
What waves are used for mobile phone networks?
radio waves because of their high frequency = greater bandwidth = large amounts of data being transferred
What affects the signal for mobile phone networks?
wet weather, microwaves are strongly absorbed by it and terrain reduces the amount of diffraction in waves
What waves are used for satellite communication
microwaves but radio waves are used for low orbit satellites
Explain how satellites communicate?
microwaves pass through the ionosphere to satellites, radio waves are reflected by the ionosphere for terrestrial communication
Define blue-tooth
wireless, short ranged radio waves that can connect electronics
State the features of Bluetooth
connects multiple devices, range of 10m, uses short radio-waves so doesn’t need line of sight, uses frequency hopping to reduce interference
State when infrared is used
low power devices like remotes
State the features of infrared
short ranged = uses line of sight, high frequency signal = large data transmits
What affects the signal for infrared waves
bright sunlight, atmospheric moistures reduces range
What waves are for Wi-Fi?
radio waves between 2.4GHz-5GHz
States the features for Wi-Fi
range of 100m, passes through walls, they can be transmitted through optic fibres/electrical wiring
