Flashcards
Waves
Cards in this deck (29)
- 1How is a stationary longitudinal wave formed?A progressive wave must travel in opposite directions to one another.
- 2What is meant by a stationary longitudinal wave?A wave that is created by blowing across one end of a closed tube. A node will therefore form and there will be the fundamental frequency given.
- 3What is the equation for the speed of sound?v=f×λ
- 4How are stationary waves in open tubes formed?Reflection of a sound wave at the open ends still occurs, contrary to beliefs, since an antinode is present at both ends.
- 5What is a transverse wave? Name some examples.A wave that oscillations at right angles to its direction of travel.
-Water waves
-Electromagnetic waves - 6What is a longitudinal wave? Name some examples.A wave that oscillates parallel to its direction of travel.
-Sound waves
-Some types of earthquakes - 7What is a progressive wave?This is when the particles of a wave oscillate vertically, however they do not move forwards or backwards and therefore carries energy without transferring any matter
- 8Name two crucial wave properties.Reflection- this can be demonstrated by the use of a ripple tank.
Refraction- this occurs when the wave changes direction as it enters a different medium, and may then speed up or slow down. - 9What is the definition of intensity?Intensity is the rate of flow of energy per unit area at right angles to the direction of travel of the wave, measured in Wm^-2.
- 10State the wave equation.v=λf.
- 11What is meant by the term diffraction?Diffraction means that when an obstacle is encountered, the wave may pass through an aperture. The wavelength does not change and the energy is distributed in each direction.
- 12What does polarisation mean?This means that a wave is manipulated to oscillate in one direction via the use of a reflective surface, which then reflects a polarised beam of light to pass through a polarising filter. And so the intensity is changed.
- 13State Malus' law.This states that the intensity of the transmitted light is proportional to the amplitude squared.
=> I= Io cos^2θ - 14What are the approximate wavelengths for the visible light range.370nm for violet to 740nm for deep red.
- 15Which properties do all electromagnetic waves have in common?- They can all travel through a vacuum
- All possess magnetic wave and an electrical wave interlock at right angles
- All travel at 3.0×10^8
- They are all transverse waves - 16Explain properties of UV-A, UV-B and UV-C radiation.UV-A has lowest frequency, and least damaging although may age skin.
UV-B may be absorbed by DNA molecules causing mutations;cancerous.
UV-C has an ionising frequency; cell mutation/destruction/cancer, almost entirely blocked by the ozone layer. - 17State the principle of superposition.This states that when two or more waves of the same type exist at the same time in the same place, the resultant is found by adding the displacements.
- 18What is constructive interference?When two waves are in phase and the amplitude of the resultant wave is twice the initial wave.
- 19What is destructive interference?This is when two waves are in antiphase, and therefore cancel each other out to create a resultant wave of zero amplitude.
- 20What is meant by coherence?This is when the waves possess the same wavelength and frequency and a fixed phase difference is between them.
- 21How can the inaccuracy of the double-slit method be overcome?By using multiple slits (via a diffraction grating).
- 22What is the nth order maximum given by using a diffraction grating?nλ=dsinθ.
- 23What happens when a white light is shone through a diffraction grating?A spectra is formed beacuse white light possesses a number of different wavelengths; each order will become a spectra.
- 24What is a standing (stationary) wave?This is where energy is stored rather than transmitted.
- 25How are standing (stationary) waves formed?When two progressive waves of the same frequency travel in opposite directions.
- 26What is the definition of a node?A node is a point at which there is no displacement of the particle at any time.
- 27What is the definition of an antinode?An antinode is a point at which the displacement of the particles in a stationary wave varies by the maximum amount.
- 28What is the frequency of the vibrations governed by?- Its mass per unit
-Its tension
-The length of the string - 29What is a diagram to show the fundamental oscillation of an instrumental string? Also what are the other harmonics illustrated by?
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- A-Levels Physics Flashcards on Waves, created by laurenb24 on 28/05/2013.
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- laurenb24 · May 2013
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- Feb 19, 2016
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