Light !! Flashcards

learn a thing or 2 the night before the test <3

You may prefer our related Brainscape-certified flashcards:
1
Q

What is regular reflection?

A

when light reflects off a very smooth surface.

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2
Q

What is diffuse reflection?

A

when light hits a rough surface, and the light scatters in many directions and doesn’t form an image.

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3
Q

What is the law of reflection?

A

The angle of incidence is equal to the angle of reflection.

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4
Q

Define incident ray.

A

the incoming ray of light.

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5
Q

Define reflected ray.

A

The ray that bounces off of the mirror.

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6
Q

Define the normal.

A

The imaginary line, perpendicular to the mirror, used to measure the angles of incidence and reflection.

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7
Q

What type of wavelength is light?

A

Visible light.

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8
Q

What type of wavelength is heat?

A

Infrared radiation.

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9
Q

Name the different wavelengths of the sun’s radiation.

A

radiowaves, microwaves, infrared, visible light, UV, X-rays, and gamma rays.

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10
Q

What types of images are formed by plane mirrors?

A

Upright, same size, same distance from mirror, laterally inverted, virtual.

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11
Q

Define lateral inversion.

A

Reversed sideways (right side is left side, vice versa).

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12
Q

Define a virtual image.

A

A visual illusion created by your brain when you look in a mirror.

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13
Q

How are virtual images created?

A

When light hits the mirror, it reflects towards your eyes creating the illusion that the light travelled in a straight line from a point inside the mirror.

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14
Q

What is refraction?

A

The bending of light.

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15
Q

What is reflection?

A

The bouncing of light off of something.

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16
Q

In which way does light bend when it enters a transparent substance?

A

Towards the normal.

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17
Q

In which way does light bend when it leaves the transparent substance?

A

Away from the normal.

18
Q

What is the refractive index?

A

The measure of how easily light travels through a substance.

19
Q

Why does light bend when going through materials of different refractive indexes?

A

Because the light travels slower the higher the refractive index.

20
Q

How do you calculate refractive index?

A

Refractive index = 3 x 10^8 (speed of light in a vacuum) / speed of light in the material.

21
Q

Why do depth illusions occur?

A

Because light from an object underwater is bent away from the normal when it leaves the water surfaces into the air. When you look at refracted light, your brain traces the light back in a straight line path.

22
Q

What is a critical angle?

A

When light is refracted so far from the normal that when it leaves, the light runs along the boundary of the two substances.

23
Q

What is total internal reflection?

A

when light is reflected from the boundary as though it was a mirror.

24
Q

When does something perform total internal reflection?

A

When the angle of incidence is greater than the medium’s critical angle.

25
Q

What are lens?

A

Transparents pieces of plastic, glass, or even jelly that is shaped to curve outwards or inwards.

26
Q

What do lens do?

A

They refract light, and focus it to form images in the eye or devices.

27
Q

What are convex lenses?

A

Lens that bulge outwards.

28
Q

What do convex lenses cause light rays to do?

A

Converge.

29
Q

What images do convex lenses produce?

A

Upright and enlarged images.

30
Q

How do convex lenses work with light?

A

When the light passes through the lens, they converge, and when the rays of light meet, they create a focal point, and form an enlarged focused image.

31
Q

What is a real image?

A

An image formed when rays of light actually meet.

32
Q

What is a concave lens?

A

A lens that curves inwards.

33
Q

What do concave lens cause light rays to do?

A

Diverge.

34
Q

What images do concave lenses produce?

A

Smaller, upright, and virtual.

35
Q

What does the retina do?

A

The cells on the retina called cone and rod cells absorb light rays and turn them into electrical signals.

36
Q

What does the optic nerve do?

A

Carries the electrical signals from the retina to the brain.

37
Q

What is the lens and what does it do?

A

A flexible structure that enables light to be focused on the retina.

38
Q

What do ciliary muscles do?

A

Change the shape of the lens.

39
Q

What does the cornea do?

A

Bends light into the lens.

40
Q

What is the vitreous humour?

A

Its the clear fluid between the lens and retina.

41
Q

What is the iris?

A

Contains dilator and sphinctor muscles to widen and contract.

42
Q

What is the pupil?

A

The opening in the iris that determines the amount of light entering the eye.