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20 Cards in this Set
- Front
- Back
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What is the normal at a point on a mirror?
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A line drawn perpendicular to the mirror
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What are the angles in a light ray reflected by a plane mirror?
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The angle of incident, the angle between the incident ran and the normal
The angle of reflection, the angle between the reflected ray and the normal |
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What does the law of reflection state?
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That the angle of incidence equals the angle of reflection.
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The image in a plane mirror is?
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The same size as the object
Upright The same distance behind the mirror as the object is in front Virtual |
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What is a real image?
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An image that can be formed on a screen, because the rays of light that produce the image actually pass through it
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What is a virtual image?
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An image that cannot be formed on a screed, because the rays of light that produce the image only appear to pass through it
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What is the refraction of light?
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The change of direction f a ligt ray when it crosses a boundary between two transparent substances.
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When a light ray refracts as it travels from air into glass, what happens to the angles?
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the angle of refraction is less than the angle of incidence
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Whan a light ray refracts as it travels from glass into air, what happens to the angles?
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The angle of refraction is more than the angle of incidence.
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What happens when light enters a more dense substance, such as going from air to glass?
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It slows down and the ray changes direction towards the normal.
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What is dispersion?
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When a ray of while tight is shone onto a triangular glass prism we can see this because a spectrum is produced.
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Which light is refracted the most and least?
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Most - Violet light
Least - Red light. |
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What is refractive index?
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a measure of how much a substance can refract a light ray.
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What is refraction of light?
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The change of direction of light as it passes from one transparent substance into another.
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What is the equation for refractive index , n,?
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speed of light in a vacuum / speed of light in the substance
sin i (incidence angle) / sin r ( refraction angle) 1 / sin c (critical angle) |
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What is the speed of light in a vacuum?
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300 000km/s
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What is the critical angle, c?
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the angle of incidence of a light ray in a transparent substance which produces refraction along the boundary.
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When does total internal reflection occur?
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When the angle of incidence of a light ray in a transparent substance is greater than the critical angle.
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What does an endoscope use?
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Total internal reflection to see inside the body directly. It contains bundles of optical fibres which are very thin, flexible glass fibres.
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Total internal reflection only takes place for a ray travelling from
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a more dense to a less dense material.
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