Term
A.1.1 Describe the basic structure of the
human eye. |
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Definition
| Can't do. Won't be able to do. |
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Term
| A.1.2 State and explain the process of depth of vision and accommodation. |
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Definition
when focusing on a near object, ciliary muscles contract and taught fibres are slack. This makes the lens thicker and shorter.
When focusing on a faraway object, ciliary muscles relax and taught fibres pull the lens longer and thinner. |
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Term
| A.1.3 State that the retina contains rods and cones, and describe the variation in density across the surface of the retina. |
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Definition
| Cones peak at the fovea, while rods are distributed more evenly, the maximums being around the cone peak. |
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Term
| A.1.4 Describe the function of the rods and of the cones in photopic and scotopic vision. |
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Definition
Photopic: cones. Related to colour vision in normal lighting. Three different cone types (R, G, B)
Scotopic: rods. Black and white in dim light.
Colour blindness is caused by the failure of one or more types of cones to respond. |
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Term
A.1.5 Describe colour mixing of light by
addition and subtraction. |
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Definition
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Term
A.1.6 Discuss the effect of light and dark, and colour, on the perception of
objects. |
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Definition
| Students should consider architectural effects of light and shadow (for example, deep shadow gives the impression of massiveness). Glow can be used to give an impression of “warmth” (for example, blue tints are cold) or to change the perceived size of a room (for example, light-coloured ceilings heighten the room). |
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Term
A.2.1 Describe the nature of standing
(stationary) waves. |
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Definition
Amplitude: all points on the wave have different amplitudes. the maximum amplitude is 2A at the antinodes. It's zero at the nodes.
Energy is not transmitted.
All points between nodes are moving in phase. |
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Term
A.2.2 Explain the formation of
one‑dimensional standing waves. |
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Definition
When two waves meet that are
of the same amplitude
of the same frequency
travelling in opposite directions |
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Term
A.2.3 Discuss the modes of vibration of
strings and air in open and in closed pipes. |
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Definition
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Term
A.2.4 Compare standing waves and
travelling waves. |
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Definition
| Amplitude, wavelength, phase and energy differ. |
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Term
A.2.5 Solve problems involving standing
waves. |
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Definition
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Term
A.3.1 Describe what is meant by the
Doppler effect. |
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Definition
| The change of frequency of a wave as a result of the movement of the source or the movement of the observer. |
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Term
| A.3.2 Explain the Doppler effect by reference to wavefront diagrams for moving-detector and moving-source situations. |
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Definition
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Term
A.3.3 Apply the Doppler effect equations
for sound. |
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Definition
| I think they're in the data booklet? If not, my finals may really be the final test I ever attend. |
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Term
| A.3.5 Solve problems on the Doppler effect for electromagnetic waves using the approximation |
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Definition
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Term
A.3.6 Outline an example in which the
Doppler effect is used to measure
speed. |
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Definition
| Vehicle speed measurements by police. |
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Term
| A.4.1 Sketch the variation with angle of diffraction of the relative intensity of light diffracted at a single slit. |
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Definition
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Term
Derive the formula
θ = λ/b
for the position of the first minimum
of the diffraction pattern produced at a single slit. |
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Definition
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Term
A.4.3 Solve problems involving single-slit
diffraction. |
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Definition
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Term
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. |
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Definition
| Students should sketch the variation where the diffraction patterns are well resolved, just resolved and not resolved. |
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Term
| A.5.2 State the Rayleigh criterion for images of two sources to be just resolved. |
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Definition
When the first minimums lie on top of the maximum intensities.
Students should know that the criterion for a circular aperture is
θ = λ 1.22/b. |
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Term
A.5.3 Describe the significance of resolution
in the development of devices
such as CDs and DVDs, the electron
microscope and radio telescopes. |
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Definition
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Term
| A.5.4 Solve problems involving resolution. |
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Definition
| Problems could involve the human eye and optical instruments. |
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Term
A.6.1 Describe what is meant by polarized
light. |
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Definition
| Light that propagates on only one plane. |
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Term
| A.6.2 Describe polarization by reflection. |
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Definition
This may be illustrated using light or microwaves.
The use of polarized sunglasses should be included.
A ray of light incident on a boundary between two media will be reflected and refracted. The reflected ray is always partially plane-polarised. If the refracted and reflected rays are at right angles to each other, then the reflected ray is completely plane-polarised. |
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Term
| A.6.3 State and apply Brewster’s law. |
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Definition
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Term
A.6.4 Explain the terms polarizer and
analyser. |
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Definition
| A polariser produces plane-polarised light from an unpolarised beam. An analyser is a polariser used to detect polarised light. |
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Term
| A.6.5 Calculate the intensity of a transmitted beam of polarized light using Malus’ law. |
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Definition
Intensity of light is proportional to the amplitude^2.
I = I0 (cos theta) ^2 |
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Term
| A.6.6 Describe what is meant by an optically active substance. |
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Definition
| Students should be aware that such substances rotate the plane of polarization. |
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Term
| A.6.7 Describe the use of polarization in the determination of the concentration of certain solutions. |
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Definition
| Optically active solution concentrations can be measured by using the proportionality between the rotation of the angle of rotation and the length of the solution and the concentration of the solution. |
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Term
| A.6.8 Outline qualitatively how polarization may be used in stress analysis. |
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Definition
| When polarised white light is passed through stressed material and then analysed, bright coloured lines are observed in the regions of maximum stress. |
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Term
| A.6.9 Outline qualitatively the action of liquid-crystal displays (LCDs). |
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Definition
| The liquid crystal is sandwiched between two glass electrodes and is birefringent. |
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Term
| A.6.10 Solve problems involving the polarization of light. |
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Definition
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