2099937
| Questão | Responda |
| A.1.1 Describe the basic structure of the human eye. | |
| A.1.2 State and explain the process of depth of vision & accommodation | Accommodation is the process by which the vertebrate eye changes optical power to maintain a clear focus on an object as its distance varies. |
| A.1.2 State and explain the process of depth of vision & accommodation (diagram) | Distant Object = lens are long & thin, tight ligaments & large pupil Near Object = lens are short & fat, slack ligaments & small pupil |
| A.1.3 State that the retina contains the rods and cones, and describe the variation in density across the surface of the retina. | Rods - not sensitive to colour; light sensitive. Not present in fovea Cones - Provide colour sensitivity; concentrated in fovea |
| A.1.4 Describe the function of the rods and cones in photopic and scotopic vision. (Spectral Response Graph) | |
| A.1.4 Describe the function of the rods and cones in photopic and scotopic vision. (Table + Colour Blindness) | Colour Blindness - no actual blindness, but a deficiency of colour vision. Cause is a fault in development of cone cells that transmit information to optic nerve. |
| A.1.5 Describe colour mixing of light by addition and subtraction | Primary Colours: Red, Green, Blue Secondary Colours: Magenta, Cyan, Yellow |
| A.2.1 Describe the nature of standing (stationary) waves. | 1.) No net propagation of energy. A standing wave does NOT move forward. 2.) Variable Amplitudes. 3.) All particles in a standing wave will either be in phase, π, or out of phase w/ each other |
| A.2.2 Explain the formation of one-dimensional standing waves. | Standing waves are the result of the interference of 2 waves of EQUAL AMPLITUDE and FREQUENCY in OPPOSITE DIRECTIONS. Nodes - Destructive Interference Antinodes - Max Constructive Interference |
| A.2.3 Discuss the modes of vibration of strings and air in open and in closed pipes. | |
| A.2.4 Compare standing waves and travelling waves. | |
| A.3.1 Describe what is meant by the DOPPLER EFFECT. | The change in frequency due to the movement of a source of sound or light OR The change in frequency due to the movement of an observer in reference to a stationary source of sound or light. |
| A.3.2 Explain the Doppler effect by reference to wavefront diagrams for moving-detector situations. | - Observer moves TOWARD a source, speed at which the wavefronts strike the "ear" become CLOSER - Observer moves AWAY from a source, speed at which wavefront strike become FARTHER (- for moving away, + for moving towards) |
| A.3.2 Explain the Doppler effect by reference to wavefront diagrams for moving-source situations. | - Source moves TOWARD an observer, the wavefronts get closer together b/c the source is "chasing" the previous wavefront - Source moves AWAY from an observer, wavefronts get farther apart b/c source is "running" from the previous wavefront. (+ For moving away, - for towards) |
| A.3.5 Solve problems on the Doppler effect for electromagnetic waves using the approximation | Should only be used when v <<< c. |
| A.3.6 Outline an example in which the Doppler effect is used to measure speed. | - Measurement of vehicle speeds. The approximation is used only when object v is much less than the transmitter, c. - Doppler shift occurs TWICE -- first for "moving observer" then "moving source" |
| A.2.5 Solve problems involving standing waves. | |
| A.3.3 Apply the Doppler effect equations for sound. | f ' = new frequency f = gen. frequency v = velocity v = speed of sound/light in medium u = speed of observer/source |
| A.4.1 Sketch the variation with angle of diffraction of the relative intensity of light diffracted at a single slit. | |
| A.4.1 Explain the meaning of diffraction. | Diffraction is the phenomenon in which waves bend around an obstacle to pass into the region when travelling. |
| A.4.3 Solve problems involving single-slit diffraction. | |
| A.4.3 Draw the diagram for single-slit diffraction. | |
| A.5.1 Sketch the variation with angle of diffraction of the relative intensity of light emitted by two point sources that has been diffracted at a single slit. | Unresolved = diffraction patterns overlap, 2 sources appear as a single source Just Resolved = CMOFM Well-resolved = two sources appear as 2 distinct sources of light |
| A.5.2 State the Rayleigh criterion for images of two sources to be just resolved. | - Just resolved: CMOFM (Central Max Overlaps First Min) - Criterion for aperture is θ = 1.22λ/b |
| A.5.3 Describe the significance of resolution in the development of devices such as CDs and DVDs, the electron microscope and radio telescopes. | Electron microscopes and radio telescopes depend on good resolution to get good data. Resolution of optical instruments can be improved by increasing its lens diameter. |
| A.5.4 Solve problems involving resolution (hint: pupil of the eyes + equation) | Depending upon how diffraction patterns overlap, the person may see two sources of light appearing as only one source. |
| A.6.1 Describe what is meant by polarized light. | A LIGHT WAVE that exists in a SINGLE PLANE, especially an electric field. |
| A.6.2 Describe polarization by reflection. (using light or microwaves) | - Light incident on a non-metallic boundary will reflect as partially / completely polarized light. |
| A.6.2 Describe polarization by reflection. (Use of Sunglasses) | - Sunglasses are used to prevent bright light or high-energy light from damaging/discomforting the eyes. - Polarized sunglasses deflect the glare of the sun |
| A.6.3 State and apply Brewster's Law | Brewster's Law: The angle at which COMPLETE POLARIZATION takes place upon reflection. (Φ - polarizing angle) |
| A.6.4 Explain the terms polarizer and analyser. | POLARIZER is a substance that passes light of a specific polarization & blocks waves of other polarizations ANALYZER is a also a polarizer (2 polarizers placed after another), but it may be used to determine 1.) if the light is polarized, 2.) the plane of polarization. If the 2 polarizer axes are right angles NO LIGHT IS TRANSMITTED. |
| A.6.5 Calculate the intensity of a transmitted beam of polarized light using Malus’ law. | When a perfect polarizer is placed in a polarized beam of light, the intensity I of the light that passes thru is given by: |
| A.6.6 Describe what is meant by an optically active substance. | One that rotates the plane of polarization of the light that passes through it. |
| A.6.7 Describe the use of polarization in the determination of concentrations of solutions. | (1) Solution placed between two crossed polaroids (liquid/chemical sol'n); (2) plane of polarization rotated by an amount that depends on concentration; (3) the angle rotation of second polarizer/intensity of transmitted light is a measure of concentration |
| A.6.8 Outline qualitatively how polarization may be used in stress analysis. | (1) Some substances become birefringent (having 2 different refractive indices) under stress; (2) place between 2 crossed polaroids, the stress is seen as bright and dark coloured regions; (3) the regions can be analyzed for weaknesses. |
| A.6.9 Outline qualitatively the action of Liquid Crystal Displays (LCDs). |
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