optics

convex mirrors

The other type of curved mirror, a convex mirror, is shaped like the outside of a bowl. This type of mirror forms only virtual images. The image is always right-side up and smaller than the actual object, which makes the object appear farther away than it really is. You can see how a convex mirror forms an image in Figure 22.14 and in the animation at the URL below. Because of their shape, convex mirrors can gather and reflect light from a wide area. This is why they are used as side mirrors on cars. They give the driver a wider view of the area around the vehicle than a plane mirror would.

concave mirrors

Some mirrors have a curved rather than flat surface. Curved mirrors can be concave or convex. A concave mirror is shaped like the inside of a bowl. This type of mirror forms either real or virtual images, depending on where the object is placed relative to the focal point. The focal point is the point in front of the mirror where the reflected rays intersect. You can see how concave mirrors form images in Figure 22.13 and in the interactive animation at the URL below. The animation allows you to move an object to see how its position affects the image. Concave mirrors are used behind car headlights. They focus the light and make it brighter. They are also used in some telescopes.

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lenses

Lenses make use of the refraction of light to create images. A lens is a transparent object, typically made of glass, with one or two curved surfaces. The more curved the surface of a lens is, the more it refracts light. Like mirrors, lenses may be concave or convex.

refraction of light

Although the speed of light is constant in a vacuum, light travels at different speeds in different kinds of matter. For example, light travels more slowly in glass than in air. Therefore, when light passes from air to glass, it slows down. If light strikes a sheet of glass straight on, or perpendicular to the glass, it slows down but passes straight through. However, if light enters the glass at an angle other than 90 , the wave refracts, or bends. This is illustrated in Figure change in speed, the more light bends.

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law of reflection

One thing is true of both regular and diffuse reflection. The angle at which the reflected rays bounce off the surface is equal to the angle at which the incident rays strike the surface. This is the law of reflection, and it applies to the reflection of all light. The law is illustrated in Figure 22.11 and in the animation at this URL:

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regular and diffuse reflection

If a surface is extremely smooth, like very still water, then an image formed by reflection is sharp and clear. This is called regular reflection. If the surface is even slightly rough, an image may not form, or if there is an image, it is blurry or fuzzy. This is called diffuse reflection. Both types of reflection are represented in Figure 22.10. You can also see animations of both types of reflection at this URL: http://toolboxes.flexiblelearning.net.au/demosites/serie In Figure 22.10, the waves of light are represented by arrows called rays. Rays that strike the surface are referred to as incident rays, and rays that reflect off the surface are known as reflected rays. In regular reflection, all the rays are reflected in the same direction. This explains why regular reflection forms a clear image. In diffuse reflection, in contrast, the rays are reflected in many different directions. This is why diffuse reflection forms, at best, a blurry image.

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plane mirrors

Most mirrors are plane mirrors. A plane mirror has a flat reflective surface and forms only virtual images. The image formed by a plane mirror is also life sized. But something is different about the image compared with the real object in front of the mirror. Left and right are reversed. Look at the man shaving in Figure 22.12. He is using his right hand to hold the razor, but his image appears to be holding the razor in the left hand. Almost all plane mirrors reverse left and right in this way.

mirrors

Mirrors are usually made of glass with a shiny metal backing that reflects all the light that strikes it. Mirrors may have flat or curved surfaces. The shape of a mirrors surface determines the type of image the mirror forms. For example, the image may be real or virtual. A real image forms in front of a mirror where reflected light rays actually meet. It is a true image that could be projected on a screen. A virtual image appears to be on the other side of the mirror. Of course, reflected rays dont actually go behind a mirror, so a virtual image doesnt really exist. It just appears to exist to the human eye and brain.

convex lenses

Convex lenses are thicker in the middle than at the edges. They cause rays of light to converge, or meet, at a point called the focus (F). Convex lenses form either real or virtual images. It depends on how close an object is to the lens relative to the focus. Figure 22.17 shows how a convex lens works. You can also interact with an animated convex lens at the URL below. An example of a convex lens is a hand lens.

concave lenses

Concave lenses are thicker at the edges than in the middle. They cause rays of light to diverge, or spread apart. Figure 22.16 shows how a concave lens forms an image. The image is always virtual and on the same side of the lens as the object. The image is also right-side up and smaller than the object. Concave lenses are used in cameras. They focus reduced images inside the camera, where they are captured and stored. You can explore the formation of images by a concave lens with the interactive animation at this URL: http://phet.colorado.edu/sims/geometric-opti

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reflection of light

Almost all surfaces reflect some of the light that strikes them. The still water of the lake in Figure 22.9 reflects almost all of the light that strikes it. The reflected light forms an image of nearby objects. An image is a copy of an object that is formed by reflected or refracted light.

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lasers

Did you ever see a cat chase after a laser light, like the one in Figure 22.21? A laser is a device that produces a very focused beam of light of just one wavelength and color. Waves of laser light are synchronized so the crests and troughs of the waves line up (see Figure 22.21). Laser light is created in a tube like the one shown in Figure 22.22. Electrons in a material such as a ruby crystal are stimulated to radiate photons of light of one wavelength. At each end of the tube is a concave mirror. The photons of light bounce back and forth in the tube off the mirrors. This focuses the light. The mirror at one end of the tube is partly transparent. A constant stream of photons passes through the transparent part, forming the laser beam. You can see an animation showing how a laser works at this URL: (1:12). MEDIA Click image to the left or use the URL below. URL: Besides entertaining a cat, laser light has many other uses. It is used to scan bar codes, for example, and to carry communication signals in optical fibers. Optical fibers are extremely thin glass tubes that are used to guide laser light (see Figure 22.23). Sounds or pictures are encoded in pulses of laser light, which are then sent through an optical fiber. All of the light reflects off the inside of the fiber, so none of it escapes. As a result, the signal remains strong even over long distances. More than one signal can travel through an optic fiber at the same time, as you can see in Figure 22.23. Optical fibers are used to carry telephone, cable TV, and Internet signals.

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optical instruments

Mirrors and lenses are used in optical instruments to reflect and refract light. Optical instruments include micro- scopes, telescopes, cameras, and lasers.

light microscopes

A light microscope is an instrument that uses lenses to make enlarged images of objects that are too small for the unaided eye to see. A common type of light microscope is a compound microscope, like the one in Figure 22.18. A compound microscope has at least two convex lenses: one or more objective lenses and one or more eyepiece lenses. The objective lenses are close to the object being viewed. They form an enlarged image of the object inside the microscope. The eyepiece lenses are close to the viewers eyes. They form an enlarged image of the first image. The magnifications of all the lenses are multiplied together to yield the overall magnification of the microscope. Some light microscopes can magnify objects more than 1000 times! For more on light microscopes and the images they create, watch the video at this URL: (7:29). MEDIA Click image to the left or use the URL below. URL:

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telescopes

Like microscopes, telescopes use convex lenses to make enlarged images. However, telescopes make enlarged images of objectssuch as distant starsthat only appear tiny because they are very far away. There are two basic types of telescopes: reflecting telescopes and refracting telescopes. The two types are compared in Figure 22.19. You can learn more about telescopes and how they evolved in the video at this URL:

cameras

A camera is an optical instrument that records an image of an object. The image may be recorded on film or it may be detected by an electronic sensor that stores the image digitally. Regardless of how the image is recorded, all cameras form images in the same basic way, as demonstrated in Figure 22.20 and at the URL below. Light passes through the lens at the front of the camera and enters the camera through an opening called the aperture. As light passes through the lens, it forms a reduced real image. The image focuses on film (or a sensor) at the back of the camera. The lens may be moved back and forth to bring the image into focus. The shutter controls the amount of light that strikes the film (or sensor). It stays open longer in dim light to let more light in. For a series of animations showing how a camera works, go to this URL: .

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instructional diagrams

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This diagram explains the concept of refraction. Light travels at a constant speed in vaccuum but travels at different speends in different media. When light travels from one medium to another, the speed of light changes causing it to appear to bend. This bending of light is called refraction. Refraction occurs when the angle of incidence (i) is not 90 degrees. In this diagram (r) is the angle of refraction. The angle of refraction is dependent on the angle o incidence as well as the speed of light in the medium through which it is travelling. XY is the boundary between the media through which light is travelling. At the point of incidence where the ray strikes the boundary XY, a line can be drawn perpendicular to XY. This line is known as a normal line (labeled NN' in the diagram).

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This diagram shows the setup of an amateur reflecting telescope. The telescope tube sits on a movable mount that allows it to point at and track objects in the sky. The mount shown is equitorial, meaning that it can be aligned to the north star for easier tracking of other stars and planets as they move ac cross the sky. The mount has a counterweight to help balance the weight of the telescope tube. The entire assembly sits on the three legs of a tripod. When pointed at the sky, light enters the optical tube through its aperture. The aperture is the circular end of the tube that allows light to enter when uncovered. Once light has entered the telescope, it is gathered and directed to the eyepiece by mirrors. The lenses in the eyepiece take this light and bring an image to focus for a human to see. The finderscope is a second smaller telescope attached the optical tube. It has lower magnification than the telescope, and this makes finding objects and pointing the telescope easier.

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This diagram explains the law of reflection and shows how light gets reflected from a surface. The law of reflection states that the angle of incidence (i) is always equal to the angle of reflection (r). The angles of both reflected and incident ray are measured relative to the imaginary dotted-line, called normal, that is perpendicular (at right angles) to the mirror (reflective surface). On the other hand, Refraction is caused by the change in speed experienced by a wave when it changes medium. The refracted ray is a ray (drawn perpendicular to the wave fronts) that shows the direction that light travels after it has crossed over the boundary. The angle that the incident ray makes with the normal line is referred to as the angle of incidence. Similarly, the angle that the refracted ray makes with the normal line is referred to as the angle of refraction. Thus, this is what the following diagram is all about.

description_image

The diagram below is about two different types of lens. A lens is a transparent piece of glass or plastic with at least one curved surface. A lens works by refraction: it bends light rays as they pass through it so they change direction. In a convex lens (sometimes called a positive lens), the glass (or plastic) surfaces bulge outwards in the center giving the classic lentil-like shape. A convex lens is also called a converging lens because it makes parallel light rays passing through it bend inward and meet (converge) at a spot just beyond the lens known as the focal point Convex lenses are used in things like telescopes and binoculars to bring distant light rays to a focus in your eyes. A concave lens is exactly the opposite with the outer surfaces curving inward, so it makes parallel light rays curve outward or diverge. That's why concave lenses are sometimes called diverging lenses. (One easy way to remember the difference between concave and convex lenses is to think of concave lenses caving inwards). Concave lenses are used in things like TV projectors to make light rays spread out into the distance.

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This diagram shows the arrangement of optics found in a refracting telescope. Llight entering the telescope first encounters the large objective lens placed a telescopes aperture the optical tube through its aperture, a circular opening at the forward end of the tube. The objective lens is convex, and it causes rays of light entered the telescope parallel to one another to converge. The eyepiece lens is located in the path of these converging rays, and brings an image to focus for the human eye.

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This Diagrams shows the different types of lenses. A lens is a clear (transparent) object (like glass, plastic or even a drop of water) that changes the way things look by bending the light that goes through it. They may make things appear larger, smaller, or upside-down. Lenses are classified by the curvature of the two optical surfaces. A lens is biconvex (or double convex, or just convex) if both surfaces are convex. If both surfaces have the same radius of curvature, the lens is equiconvex. A lens with two concave surfaces is biconcave (or just concave). If one of the surfaces is flat, the lens is plano-convex or plano-concave depending on the curvature of the other surface. A lens with one convex and one concave side is convex-concave or meniscus. It is this type of lens that is most commonly used in corrective lenses. If the lens is biconvex or plano-convex, a collimated beam of light passing through the lens converges to a spot (a focus) behind the lens. In this case, the lens is called a positive or converging lens.

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This diagram shows the arrangement of optics found in a reflecting telescope. Light enters the optical tube through its aperture, a circular opening at the forward end of the tube. When light enters the telescope, it encounters a concave reflecting mirror at the back of telescope tube. This large reflecting mirror is called the objective. Light reflected from the objective converges on a small right angle mirror at the center of the optical tube. This mirror reflects the gathered light to the eyepiece. The lenses in the eyepiece take this light and bring an image to focus for a human to see.

questions

formation of a clear image by light reflected from a very smooth surface

a. convex

b. laser

c. concave

-->  d. regular reflection

e. optics

f. image

g. diffuse reflection

A convex lens

a. is thicker at the edges than in the middle.

b. forms only real upside-down images.

-->  c. may form enlarged or reduced images.

d. causes rays of light to diverge.

device that produces a very focused beam of light of just one wavelength

a. convex

-->  b. laser

c. concave

d. regular reflection

e. optics

f. image

g. diffuse reflection

Concave mirrors are used

a. as side mirrors on cars.

-->  b. behind car headlights.

c. in compound microscopes.

d. in cameras.

curving outward like the outside of a bowl

-->  a. convex

b. laser

c. concave

d. regular reflection

e. optics

f. image

g. diffuse reflection

The optical instrument that produces a beam of very focused light is a

-->  a. laser.

b. microscope.

c. telescope.

d. none of the above

Which surface is most likely to result in diffuse reflection?

a. completely still water in a puddle

-->  b. choppy water in a lake

c. a plane glass mirror

d. a convex mirror

copy of an object that is formed by reflected or refracted light

a. convex

b. laser

c. concave

d. regular reflection

e. optics

-->  f. image

g. diffuse reflection

formation of a blurry image by light reflected from a rough surface

a. convex

b. laser

c. concave

d. regular reflection

e. optics

f. image

-->  g. diffuse reflection

A compound microscope contains

a. convex lenses

b. plane mirror

c. convex mirror

-->  d. two of the above

curving inward like the inside of a bowl

a. convex

b. laser

-->  c. concave

d. regular reflection

e. optics

f. image

g. diffuse reflection

study of visible light and the ways it can be used

a. convex

b. laser

c. concave

d. regular reflection

-->  e. optics

f. image

g. diffuse reflection

Moving the lens of a camera controls the amount of light that enters the camera.

a. true

-->  b. false

A laser beam consists of photons of light of a single wavelength.

-->  a. true

b. false

A reflecting telescope does not refract light.

a. true

-->  b. false

Magnifications of all the lenses of a microscope are added to yield the overall magnification of the

a. true

-->  b. false

Light refracts when it enters a new medium at an angle other than 90 .

-->  a. true

b. false

Only mirrors reflect light and form images.

a. true

-->  b. false

All mirrors can form virtual images.

-->  a. true

b. false

The image formed by a plane mirror looks exactly like the object in every way.

a. true

-->  b. false

The focal point of a concave mirror is the point in front of the mirror where reflected rays intersect.

-->  a. true

b. false

A concave mirror can form only virtual images.

a. true

-->  b. false

The image formed by a convex mirror is always upright and reduced in size.

-->  a. true

b. false

Light travels more quickly through glass than through air.

a. true

-->  b. false

The more curved the surface of a lens is, the more it refracts light.

-->  a. true

b. false

The lens in a camera is a convex lens.

a. true

-->  b. false

A refracting telescope uses a convex lens to collect and focus light.

-->  a. true

b. false

The image of an object that is formed by a concave mirror is always

a. real.

b. virtual.

c. upright.

-->  d. none of the above

Which statement about concave lenses is true?

a. They are thicker in the middle than at the edges.

-->  b. They cause rays of light to diverge.

c. They form upside-down images.

d. They form enlarged images.

Whether a convex lens forms a real or virtual image depends on

-->  a. where the object is located relative to the focus.

b. whether the object is placed right-side up.

c. how large the object is.

d. how curved the lens is.

Optical instruments include

a. microscopes.

b. telescopes.

c. cameras.

-->  d. all of the above

Both microscopes and telescopes use

a. concave lenses.

-->  b. convex lenses.

c. convex mirrors.

d. all of the above

The image produced by a camera is

a. virtual.

b. enlarged.

c. reduced.

-->  d. two of the above

A laser device produces a very focused beam of light by

-->  a. lining up the crests and troughs of light waves.

b. using only very high frequencies of light waves.

c. using convex lenses to enlarge light waves.

d. shining light waves through an optical fiber.

diagram questions

question_image

Which letter indicates a double concave lens?

-->  a. N

b. D

c. S

d. F

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Identify the double concave lens

a. S

-->  b. N

c. D

d. X

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Which label indicates the plano-concave part in the diverging lens?

a. N

-->  b. M

c. S

d. A

question_image

What three parts make up converging?

a. NEGATIVE MENISCUS

b. PLANOCONCAVE

-->  c. BICONVEX, PLANOCONVEX, AND POSITIVE MENISCUS

d. BICONCAVE

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Which label marks a double convex lens?

a. K

-->  b. U

c. S

d. C

question_image

Which is the convex lens?

a. S

-->  b. U

c. L

d. K

question_image

Which illustration shows a plano-convex lens?

a. S

b. U

-->  c. E

d. W

question_image

Which label marks a double concave lens?

a. D

b. W

-->  c. U

d. S

question_image

What does the label Y represent?

a. BLIND SPOT

b. VANISHING POINT

c. DISTANCE

-->  d. FOCUS

question_image

Please identify the point labelled Y.

-->  a. FOCAL POINT

b. CONVEX POINT

c. FOCUS POINT

d. LENS POINT

question_image

Which label indicates the focus of the concave lens?

-->  a. J

b. F

c. E

d. K

question_image

Identify the lens

a. D

b. L

-->  c. K

d. C

question_image

What is the Telescope part Labeled L?

a. SECONDARY MIRROR

-->  b. EYEPIECE

c. PRIMARY MIRROR

d. IMAGE

question_image

Which label refers to the primary mirror?

a. A

-->  b. S

c. X

d. L

question_image

Which letter represents the eyepiece?

-->  a. L

b. S

c. A

d. X

question_image

Which letter corresponds to the part that reflects light into the eyepiece?

a. A

b. S

-->  c. X

d. L

question_image

Which letter to closest to the point labeled S?

-->  a. C

b. X

c. A

d. L

question_image

Which label shows the Lens?

-->  a. J

b. D

c. A

d. M

question_image

Which label stands for the lens?

-->  a. J

b. M

c. A

d. D

question_image

The label A represents the title of this diagram. What would be a good title for the diagram?

a. WAVELENGTHS OF SPACE OBJECTS

b. ANGLE OF INCIDENCE

-->  c. REFRACTING TELESCOPE

d. NORMAL ANGLE IN TELESCOPE

question_image

What does J represent?

a. IMAGE

b. NOTHING

-->  c. LENS

d. EYEPIECE

question_image

Which letter depicts the lens?

a. A

b. D

-->  c. J

d. M

question_image

Identify the mounting rail

-->  a. U

b. E

c. T

d. W

question_image

Identify the scope tube in this picture

a. C

-->  b. T

c. W

d. K

question_image

Which letter represents the mounting rail?

a. W

b. K

c. C

-->  d. U

question_image

Where is the scope tube?

-->  a. T

b. C

c. W

d. K

question_image

By what letter is the objective lens represented in the diagram?

a. C

-->  b. R

c. F

d. E

question_image

Where is the light in this picture?

a. R

-->  b. F

c. E

d. C

question_image

Which label refers to the objective lens?

-->  a. P

b. K

c. D

d. X

question_image

Which letter represents the lens in this telescope?

a. P

b. F

c. W

-->  d. E

question_image

Which is the eyepiece focal length?

-->  a. U

b. X

c. C

d. W

question_image

Which letter identifies the lens?

a. R

b. M

-->  c. H

d. Y

question_image

Which part is responsible for focusing the image onto another mirror?

a. R

-->  b. Y

c. M

d. H

question_image

Which label stands for the mirror?

-->  a. D

b. S

c. BOTH S AND X

d. X

question_image

Which mirror reflects the rays coming from mirror S?

a. Y

b. K

c. D

-->  d. X

question_image

What is the part of the telescope represented with the letter M?

a. FOCUSER

b. MOUNT

-->  c. EYEPIECE

d. OPTICAL TUBE

question_image

Which label shows the optical tube?

a. V

b. W

-->  c. P

d. E

question_image

The concave lens has the following characteristics:

a. Thin edges with a thin middle area

-->  b. Thicker egdes with a thinner middle area

c. Thin edges with a thick middle area

d. Thicker edges with a thick middle area

question_image

Identify the lens that is used in cameras.

a. Plano-convex

b. Diverging meniscus

c. Double convex

-->  d. Double concave

question_image

What is a lens that is concave on both sides called?

a. convex lens

b. Concave lens

-->  c. Biconcave lens

d. Plano concave lens

question_image

How many types of converging lens are there?

a. 4

b. 6

-->  c. 3

d. 5

question_image

How many types of diverging lens are there?

-->  a. 3

b. 4

c. 1

d. 2

question_image

Biconcave belongs to what type of lens?

a. Simple

-->  b. Diverging

c. Compound

d. Converging

question_image

Which of these is not converging?

-->  a. biconcave

b. plano-convex

c. positive meniscus

d. biconvex

question_image

What is the widest image shown in the diagram?

a. negative meniscus

-->  b. biconvex

c. plano-convex

d. positive meniscus

question_image

What is between the biconvex and positive meniscus?

a. Negative meniscus

b. Biconcave

-->  c. Planoconvex

d. Planoconcave

question_image

How many types of lenses are shown in the diagram?

-->  a. 6

b. 5

c. 7

d. 8

question_image

Which of these causes light to converge?

-->  a. Double Convex Lens

b. Negative Meniscus Lens

c. Plano-Conclave Lens

d. Double Conclave Lens

question_image

How many types of lens are there?

a. 4

b. 5

c. 3

-->  d. 6

question_image

Which of these do not converge light?

a. double convex lens

b. positive meniscus lens

-->  c. double concave lens

d. plano-convex lens

question_image

Where is the focal point?

a. Over the lines

b. Next to the lines

-->  c. Where the lines are closer

d. Below the lines

question_image

What is the point where the light rays converge called?

a. distortion

-->  b. focus

c. concave

d. lens

question_image

What does a concave lens do to light?

-->  a. diffract it

b. focus it

c. refract it

d. reflect it

question_image

What is the point at which rays or waves meet after reflection or refraction?

-->  a. Focal Point

b. Concave Point

c. Converse Point

d. Diverse Point

question_image

What is the name for the distance between the focal point and the mid-line of the lens in this diagram?

-->  a. focal length

b. aperture

c. lens diameter

d. convex length

question_image

How many intersection points are needed to achieve focus?

a. 2

b. 0

-->  c. 1

d. 3

question_image

How many parts are shown in the diagram below?

-->  a. 3

b. 5

c. 4

d. 6

question_image

What is the term for the distance between the lens and the focal point?

a. focus

b. convex

-->  c. focal length

d. length

question_image

If the incident ray was incident at an angle of zero degrees, what would be the angle of the refracted ray?

a. 45 degrees

b. Greater than 90 degrees

c. 90 degrees

-->  d. Zero degrees

question_image

Which ray is the incoming ray?

a. Normal ray

b. Reflected ray

-->  c. Incident ray

d. None

question_image

What is the angle that is created by the Refracted Ray?

a. Angle of incident

b. Normal

-->  c. Angle of refraction

d. Incident ray

question_image

What would happen to angle of refraction if angle of incident decreases?

a. angle of refraction remains same

-->  b. angle of refraction also decreases

c. angle of refraction increases

d. not enough information

question_image

Which is the angle of incidence above water?

a. C

b. D

c. B

-->  d. A

question_image

What are the name of the rays that strike the water?

a. Indirect Rays

b. Reflected Rays

-->  c. Incident Rays

d. Direct Rays

question_image

How many degrees is the angle of refraction?

a. 30

-->  b. 45

c. 15

d. 75

question_image

If light hits liquid A 30 degrees from the liquid's surface, how many degrees from normal is the light refracted?

-->  a. 45 degrees

b. 70 degrees

c. 50 degrees

d. 60 degrees

question_image

A light that passes through a transparent material exits in what angle relative how it entered?

a. opposite angle

b. lesser angle

-->  c. same angle

d. greater angle

question_image

How many times does light refract through a glass window?

-->  a. 3

b. 4

c. 1

d. 2

question_image

How many types of refractive index are there?

a. 1

b. 4

-->  c. 3

d. 2

question_image

How long is the glass medium?

a. 5 mm

b. 2 mm

c. 9 mm

-->  d. 6 mm

question_image

At least how many mediums are required for reflection of light?

a. 3

-->  b. 2

c. 4

d. 1

question_image

How many times is normal represented on the diagram?

a. 4

b. 1

-->  c. 2

d. 3

question_image

Different parts of the air

a. full glass

-->  b. air medium

c. strong air

d. mild air

question_image

Among water, glass, and diamond, which of these refracts light the most?

a. glass

-->  b. diamond

c. cannot be determined

d. water

question_image

How many angles there are in the diagram below?

a. 4

-->  b. 3

c. 5

d. 1

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How many types of rays can form based on the material?

-->  a. 2

b. 1

c. 4

d. 3

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If the incident angle becomes smaller what happens to the reflected angle?

a. Stays the same

b. Becomes larger

c. Becomes horizontal

-->  d. Becomes smaller

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What happens to the light rays as they hit water, glass, etc?

-->  a. They change directions

b. They turn around

c. Nothing happens

d. They continue in the same direction

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Which of the following sentences is the one correct?

-->  a. The light ray refracts when it passes from air to water/glass.

b. The light ray doesn't refract when it passes from air to water/glass

c. The ligh ray only refracts when it passes from water to glass.

d. The light rays never refracts.

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How many light rays were refracted in the diagram?

a. 3

b. none

-->  c. 2

d. 1

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What is a line (straight or curved) that is perpendicular to the light's wave fronts?

a. Energy Rays

b. Sun Rays

c. Optic Rays

-->  d. Light Rays

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Identify the optics system shown below.

a. Reflection

b. Concave Lens

-->  c. Refraction

d. Convex Lens

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What is the angle between an incident ray and the normal?

-->  a. Angle of incidence

b. Angle of refraction

c. Angle of glass

d. Angle of air

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At what angle does the light pass straight through a glass?

a. 45

b. 60

-->  c. 90

d. 30

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How many angles are shown in the diagram?

a. 3

b. 5

-->  c. 2

d. 4

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What is the angle between refracted ray and the normal line called?

a. angle of reflection

-->  b. angle of refraction

c. angle of incidence

d. boundary

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Before reaching the eyepice, what does the Image hit?

-->  a. A primary mirror and a secondary mirror

b. Nothing

c. Only a primary mirror

d. Only a secondary mirror

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From where do you have to watch to see the image, using a reflecting telescope?

-->  a. Eyepiece

b. Primary mirror

c. Image

d. Secondary mirror

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How many mirrors does the telescope have?

a. 3

b. 4

c. 1

-->  d. 2

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How many parts are there in a reflecting telescope?

a. 5

-->  b. 3

c. 2

d. 4

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How many lenses are used in the setup shown in the diagram?

a. 4

b. 3

-->  c. 2

d. 1

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What does the lens do?

a. It makes the image small

b. It distorts the image

c. It transfers the image to the eye

-->  d. It magnifies the image

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What happens if the lens is removed from the telescope?

a. The image is darker.

b. The image is upside-down.

-->  c. The image will not focus.

d. The telescope functions as normal.

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What part protects the elevation adjustment drum?

-->  a. protection cap

b. scope tube

c. ocular assembly

d. mountaing rail

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Which part adjusts the elevation?

a. ocular assembly

-->  b. Elevation adjustment drum

c. protection cap

d. mounting rail

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How many parts of the ocular assembly are there?

a. 5

b. 6

c. 4

-->  d. 2

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How many parts of the telescope are identified in the image?

a. 7

b. 8

c. 6

-->  d. 9

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How does a telescope affect what you see?

a. Has no effect on the size.

-->  b. Makes images appear bigger.

c. Makes images darker.

d. Makes images appear smaller

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What is directly underneath the protection cap?

a. apperture in second focal plane

b. picture reversal assembly

c. ocular assembly

-->  d. elevation adjustment arm

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Where does the light travel first?

a. The center

b. The eyepiece

c. The subjective lens

-->  d. Through the objective lens

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Light enters through the...

a. light ray

-->  b. objective lens

c. eyepiece

d. f

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Light goes toward what?

-->  a. the eyepiece

b. lens

c. objective

d. focal light

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The objective lens directs the light towards which part?

a. Object

-->  b. Eyepeice

c. Air

d. Lens

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How many lenses does the simple telescope have?

a. 1

b. 3

c. 4

-->  d. 2

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How many parts are shown in the diagram below?

-->  a. 4

b. 5

c. 2

d. 3

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What part does light from the environment first come through?

a. light ray

b. eyepiece

-->  c. objective lens

d. f

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Where does light enter in the top telescope?

a. eyepiece

-->  b. objective lens

c. tripod

d. mount

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In a refracting telescope, what does light pass through before reaching the eyepiece?

a. Concave lens

b. Objective mirror

c. Flat mirror

-->  d. Objective lens

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Which of the following is NOT a part of a telescope?

a. Objective Lens

b. Eyepiece

c. Flat Mirror

-->  d. Water Filter

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How many mirrors are inside the lower telescope?

a. 1

b. 4

-->  c. 2

d. 3

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How many types of telescope are shown in the diagram?

a. 4

-->  b. 2

c. 1

d. 3

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What does the viewer look through to see the magnified image?

a. Eyepiece focal length

b. Objective lense

-->  c. Eyepiece lens

d. Objective focal length

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What is the part of the telescope that your eye looks through to see a distant object?

-->  a. Eyepiece

b. Objective

c. Focus

d. Focal Length

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How many lenses are shown in the diagram?

-->  a. 2

b. 3

c. 1

d. 4

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How many types of lens are used in simplified refracting telescope?

a. 3

b. 1

-->  c. 2

d. 4

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What happens if the objective lens is removed from the telescope?

a. The image remains the same.

b. The image is shown upside-down.

c. The image is darker.

-->  d. The image will not focus.

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How many mirrors are in a Newtonian reflector?

-->  a. two

b. four

c. three

d. five

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How many parts are labels in the Newtonian reflector?

a. 5

b. 4

-->  c. 2

d. 3

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If the smaller mirror is removed, what happens?

-->  a. No image appears to the eyepiece.

b. The image in the eyepiece is brighter.

c. The image in the eyepiece is upside-down.

d. The image in the eyepiece is darker.

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What is shown in the diagram?

a. Life Cycle

b. Light Rays

c. Mirror Glass

-->  d. A Newtonian Reflector

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What supports the telescope?

a. Aperure

b. Eye piece

-->  c. Mount

d. Optical tube

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When objects in the distance are blurry, this piece should be adjusted.

-->  a. focuser

b. mount

c. optical tube

d. eyepiece

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Which of the following is NOT a part of a telescope?

a. Finderscope

-->  b. Hopper

c. Eyepiece

d. Optical Tube

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How many parts of the telescope are in the diagram below?

a. 5

b. 6

c. 8

-->  d. 7

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What kind of lens are used in telescopes?

a. Diffuse glass

-->  b. Convex

c. Concave

d. Mirror

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Identify the lens

a. R

b. H

-->  c. Y

d. M

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Identify the plano-convex

a. X

b. S

-->  c. M

d. N

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Identify the eyepiece

-->  a. E

b. R

c. C

d. U