Optics Pt.2 Flashcards

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1
Q

What is the Mirror Equation?

A

1/f = 1/Do+1/Di

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2
Q

What is Do and Di?

A

Do = distance of object
Di = Distance of image

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3
Q

What does it mean in Di is positive? Negative?

A

Di is pos = Real image
Di is neg = Virtual image

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4
Q

What does it mean if F is neg or pos?

A

F (-) = Concave mirror
F(+) = Convex Mirrpr

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5
Q

What is the Magnification equation?

A

M = Hi/Ho = -Di/Do

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6
Q

What is Hi and Ho

A

Hi = Height of image

Ho = Height of Object

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7
Q

What does it mean if the height of the image is postitive?

A

If Hi/m is pos = Upright and virtual

If Hi/m is neg = Inverted/upside down and Real

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8
Q

What is Do always?

A

Positive

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9
Q

What does it mean if Di is positive? Negative?

A

Di pos = image is real
Di neg= image is virtual

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10
Q

Ho is always ?

A

Positive

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11
Q

What does it mean when image is upright? Inverted?

A

Hi is positive when upright
Hi is negative when inverted

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12
Q

What does it mean if light can pass through F in a convex lens? What about when it can’t in a concave?

A

When light can pass through F in a convex lense F is positive

When light cannot pass through F in a concave lense F is negative

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13
Q

In general what does + and - mean?

A

+ means real or upright
- means virtual or inverted

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14
Q

What is diverging lense lost

A

L - between F & O
O- upright
S- smaller
T- virtual

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15
Q

When object is beyond 2F in converging state lost

A

L - btw C and F
O- inverted
S- smaller
T- real

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16
Q

When object is at 2F in converging what is lost

A

L- at 2F
O- inverted
S- same size
T-real

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17
Q

Between 2F and F what is LOST converging

A

L- beyond 2F
O- inverted
S- bigger
T- real

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18
Q

At F lost converging

A

No image forms

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19
Q

Between F and O state lost converging

A

L- beyond 2F
O- upright
S- bigger
T- virtual

20
Q

Describe a converging lense

A

Lense that are thickest in middle and cause incident parallel to converge thro single point after refraction

21
Q

Describe diverging lenses

A

Thinnnest in middle and cause incident parallel light rays to spread apart after refraction

22
Q

What are lenses made of

A

Glass and plastic

23
Q

What is refraction

A

The bending /change of direction of light when travelling from one medium to another one

24
Q

What happens when light passes into a medium that is more dense? Less?

A

When light passes through a medium that is more dense, it will slow down, when it passes through something less dense, it will speed up

Dense is like thicker, so water is more dense than air. Makes sense cuz passing through water will slow u down rather than air

25
Q

What is the speed of light in a vacuum, water and acrylic?

A

Vacuum: 3.00 x 10^8 m/s
Water: 2.26 x10^8 m/s
Acrylic : 1.76 x 10^8 m/s

26
Q

When does light bend away from Normal, give an example what about towards?

A

Light bends AWAY from normal when light goes into a less dense material, speed of light is greater. eg air

Light bends TOWARDS the normal when speed of light is less in a medium, or when a medium is more dense. Eg, water

27
Q

What does fast stand for

A

F- faster
A-away
S-slower
T-towards
Used to describe air to water ray, Lea dense to more dense therefore bending away

28
Q

As incident angle increases what happends to refraction angle

A

Increases

( angle is ray to normal)

29
Q

What is refractive index

A

“N”

It is the measure of optical density, the higher the value the more optically dense it is eg zircon (1.92) is more optically dense than glycerin (1.47)

30
Q

What is a critical angle?

A

When light refracts at 90 degrees

31
Q

What’s a total internal reflection

A

When the incidence angle exceeds the critical angle total internal reflection happends

32
Q

What are the conditions for total internal reflection

A
  1. Second medium has to be less dense and lower index of refractions. ,love from more dense to less dense
  2. Incident angle exceeds CA
33
Q

What is lucite wrapped in and why does any life enter reflect?

A

Lucite is wrapped in cladding of lower index of refraction

Lucite has a very small CA,any light that enters will reflect allowing waves to travel very far

34
Q

What is the CA first glass? Diamond?

A

Glass: 41.4, angle of incidence is always 45. Results in clear image formed

Diamond: 25 ca, sparkle comes from tir

35
Q

What are the 3 seniors and describe them for TIR

A
  1. The normal one where it moves towards or away
  2. When the CA and TIR are equal, it refracts at 90 degrees
    3.TIR, when the second medium has less density, and incident angle is bigger then CA
36
Q

Cornea

A

Transparent front part of eye that covers iris and pupil. Together with lens and the cornea will refract light

37
Q

Pupil

A

Hole that allows light into the eye

38
Q

Iris

A

The eye colour, circular band of muscle that controls amount of light entering

39
Q

What happens in dim and bright light

A

Dim - pupil dilates

Bright-pupil constricts

40
Q

Retina

A

The inner lining at the back of the eye, contains photoreceptors which are sensitive to light images formed are inverted

41
Q

Blind spot

A

Has no photoreceptors, cannot detect light. Optic nerve connects eye to brain

42
Q

what do muscles do to focus on distant objects? Close objects?

A

Relax which makes lens flatter and thinner for distant objects

Muscles contract making lense thicker and rounder, to focus on close objects

43
Q

Myopia

A

Nearsighted

Eye is too long or cornea is too curbed, image appears before Retina

Hiw to fix?

Diverging lenses spread out rays just right amount before they enter the eye so the image will converge properly onto retina

44
Q

Hyperopia

A

Far sightedness

Eye is too short or lems is flatter, image appears behind retina

How to fix

Converging lenses converge rays just the right amount before entering eye to image will converge properly onto retina

45
Q

Presbyopia

A

Stuff lenses become a problem with age making it difficult for cillary muscles,especially to change shape of lense

Can’t focus on nearby objects

Nearsighted person develops presbyopia, bifocals are required

46
Q

Astigmatism

A

Irreg shaped cornea

Football shapes rather than baseball

Results in blurry vision