Science C1+2 Flashcards
Angle of incidence
The angle of incidence is measured from the normal. An angle made by a light ray or wave hitting a surface and the line perpendicular to that surface. An example of an angle of incidence is the angle between a light hitting a table and a line perpendicular to the table. According to the law of reflection, the angle of incidence is equal to the angle of reflection.
Angle of reflection
The angle between the reflected ray and the normal is the angle of reflection. OR The angle that a ray of light or the like, reflected from a surface, makes with a normal to the surface at the point of reflection.
angle of refraction
Refraction is the bending of the path of a light wave as it passes across the boundary separating two media. In such a case, the refracted ray will be closer to the normal line than the incident ray is; this is the FST rule of refraction. Refraction is caused by the change in speed experienced by a wave when it changes medium.
binocular
They are simply two short refracting telescopes fixed together. Binoculars are not as powerful as telescopes but they are much more convenient. Binoculars have two reflecting prisms on each side. binoculars take advantage of lenses to manipulate light.
concave lens
A concave lens is thinner in the centre than at the edges. As parallel rays pass through a concave lens, they are refracted away from the centre of the lens. So as light passes through a concave lens, the light rays diverge or spread out, and they will never meet on the other side of the lens.
convex lens
A convex lens curves outward and is thicker in the middle than at the edges. The technical name for a convex lens that curves outward on both sides is a double convex lens, but it’s usually just called a convex lens. As parallel light rays travel through a convex lens, they are refracted toward the centre of the lens. So as light passes through a convex lens, the rays move toward each other. The light rays cross at the focal point of the lens. Convex lenses bend parallel light rays to a single point. As a result, the concentrated light energy at that point is hot enough to burn skin and can start fires. The ability to bring light rays together makes a convex lens useful for two reasons. First, it can act as a light collector, much like a concave mirror. This is why a convex lens is used in a refracting telescope. It collects and focusses starlight. Second, a convex lens forms a real image. The light rays actually meet at a point, and the image can be projected onto a screen.
converge
light converges through convex lenses, and light diverges through concave lenses. By putting these lenses in front of the eye, you can alter the angle at
which light enters the eye. For people whose lenses cannot converge light enough, convex lenses are prescribed.
concave mirror
A concave mirror has a surface that curves inward like a bowl. Like any other mirror, concave mirrors obey the law of reflection. However, when parallel light rays approach a curved surface and strike at different points on the curve, each ray will reflect at a slightly different direction. These rays all head to a common point, called the focal point. concave mirrors are good at collecting light and bringing it to a single point. This is why concave mirrors are ideal for reflecting telescopes where you want to gather as much dim light as possible.
convex mirror
A mirror with a surface curved outward is called a convex mirror. As you might expect, it does the opposite of a concave mirror. Instead of collecting light, it spreads out light rays. A convex mirror reflects parallel rays of light as if they came from a focal point behind the mirror.
Focal point
rays all head to a common point, called the focal point. the point at which rays or waves meet after reflection or refraction, or the point from which diverging rays or waves appear to proceed. (for concave) If an object is farther from the focal point, the image is upside down. If the object is between the focal point and the mirror, the image appears upright and enlarged.
Incident rays
An incident ray is a ray of light that strikes a surface. The angle between this ray and the perpendicular or normal to the surface is the angle of incidence.
intensity
Ray diagrams can help explain why the brightness, or intensity, of a light changes with distance. Figure 2.3 shows the same number of rays leaving the light source, but fewer hit your eyes as you move farther away.
Luminous
A light source is luminous; it produces light. Light
from a light source (the sun, a lamp) bounces or reflects off the pencil and hits your eyes.
microscope
All microscopes allow you to see great detail by combining the power of at least two lenses. These two lenses are the eyepiece and the objective. When a light
source shines through the specimen, a large image is produced that you can see by looking through the eyepiece. microscopes take advantage of lenses to
manipulate light.
Non- luminous
Pencils and other opaque objects are non-luminous, meaning they don’t produce light. The light that gets to your eyes from the pencil is actually light reflected from a
light source.
normal line
a line perpendicular to the mirror at the point of reflection is called the normal. angles are measured from the normal.
opaque
Opaque materials do not allow any light to pass through them. They absorb or reflect the light that hits them. Since light cannot get through an opaque object, a shadow is created behind it. Wood, metal, and brick are examples of opaque objects.
optical device
With a little help from optical devices, you can see amazing images from across the galaxy or inside a living, breathing human being. An optical device is any technology that uses light. An optical device can be as simple as a mirror, or as complex as the Hubble Space Telescope. ex: binoculars, lasers, microscopes, telescopes
parallel
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perpendicular
idk
plane mirror
Plane mirrors (flat mirrors) provide the clearest reflections. Using plane mirrors, you can investigate how reflected light behaves. When a ray of light hits a plane mirror at an angle, it bounces off the mirror surface at exactly the same angle.
ray diagram
Scientists use ray diagrams to show how light travels. The light traveling from a source is shown as straight lines called rays. Each ray ends with an arrow to indicate the direction of travel. Although ray diagrams are useful, they don’t show the complete picture. Light rays travel away from a light source in every direction. ray diagrams are useful because they can illustrate how light behaves in different situations. Ray diagrams can help explain why the brightness, or intensity, of a light changes with distance.
Real image
Real images are those where light actually converges. Real images occur when objects are placed outside the focal length of a converging lens or outside the focal length of a converging mirror. a convex lens forms a real image.
Reflected Rays
The ray of light traveling from a surface where the incident ray strikes a surface
Reflection
the throwing back by a body or surface of light, heat, or sound without absorbing it.
Regular reflection
Regular reflection occurs when light rays hit a smooth surface. The incoming rays travel parallel to one another. When these rays strike a smooth surface, they all bounce off in the same direction, and so the reflected rays stay parallel to one another. Regular reflection
produces a clear image.
Telescope
Telescopes provide enlarged images of distant objects by using lenses and mirrors, or a combination of both, to collect light from distant objects and bring it to your eyes. Usually telescopes are used to collect light from space, allowing astronomers to see objects that they could not see with the unaided eye.
translucent
Translucent materials allow some, but not all, light to pass through. A frosted window pane is a good example of a translucent material. Some light can pass through, but you can’t see what’s on the other side of the frosted glass in any detail.
transparent
Transparent materials, such as glass or clear plastic, can transmit light, meaning light travels straight through them. That’s why you can see clearly through a window pane.
virtual image
virtual images are locations from where light appears to have converged.
refracting telescopes
Refracting telescopes have two lenses, one on each end of a long tube. The larger lens is the objective lens that gathers light and focusses the rays toward the eyepiece, which in turn allows you to see the object larger than it appears with the unaided eye.
reflecting telescopes
Reflecting telescopes use a large circular mirror that curves inward. This curved surface gathers light extremely well. Another mirror inside the telescope directs light to the eyepiece, which leads to your eye.
diffuse reflection
When light rays strike a rough or uneven surface, diffuse
reflection occurs. When the light rays hit the surface, they reflect, but due to the rough surface, each of the rays is reflected at a different angle. So the reflected rays do not remain parallel.
diverge
light rays spread out
Pythagoras
thought light was beams that came from a person’s eyes
in straight lines.
Euclid
light was reflected
light travels in straight lines
Ptolemy
Light bends when it travels from air to glass
al-Haythem
wrote a book to help explain optics, being
the first to accurately describe how vision worked
Isaac Newton
showed that white light is a mixture of
different colors of light
Ole Romer
determined the speed of light
Albert A. Michelson
– was able to determine more
accurately the speed of light 🡪 299 798 km/s
Archimedes
planned for the use of mirrors in war to burn
enemy ships
4 properties of light
Light travels in straight lines.
Light can be reflected.
Light can bend.
Light is a form of energy.
Characteristic
It has a large mirror to collect and focus the light from distant stars. It can produce much higher quality images than ground-based telescopes because light does not have to travel through the interference of Earth’s atmosphere.
OR
Telescopes both magnify and collect light. The magnifying power of his telescopes allowed him to see Venus, and the light-collecting ability of the microscope allowed him to see the faint objects around Jupiter.
