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Optics Block 2 > week 1 > Flashcards

week 1 Flashcards

1
Q

If an image is minified and erect, what kind of lens is it?

A

NEGATIVE LENS

CONCAVE LENS

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2
Q

What are the three rays we draw for negative lenses?

A
  1. ray parallel to optical axis and the lens diverges the ray as if it originated from the focal point
  2. ray “targeting” the focal point, but ray becomes parallel after hitting the lens
  3. ray crossing the center of the lens continues and does not change paths
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3
Q

For these rays, you must assume…

A
  1. lens is thin

2. environment is the same before and after the lens(cornea doesn’t follow this rule)

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4
Q

Where does an image from with a negative lens?

A

-you dot dot dot back to where the divergiving rays would converge/originate from

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5
Q

If focal length=-25cm, what is the lens power?

A

-4D

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6
Q

If rays are collimated, what is the vergence?

A

ZERO. OBJECT/IMAGE IS AT INFINITY

-image vergence is equal to the lens power

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7
Q

equation for imaging

A

Xo+P=Xi
XO=1/xo
P=1/f
XI=1/xi

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8
Q

Object is located 50mm in front of a lens, object beam vergence is…

A

-20D

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9
Q

When is an image virtual

A

when you have to do the dot dot dot backwards

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10
Q

If an image is larger and erect, what kind of lens?

A

PLUS LENS

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11
Q

If an image is smaller and erect, what kind of lens is it?

A

MINUS LENS

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12
Q

Negative lens imaging

A

-image is virtual, erect, smaller, and in object space

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13
Q

If object is located distance f in front of the plus lens of a focal distance f, object beam vergence is…

A

-P

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14
Q

If image beam vergence is zero, what is image location?

A

INFINITY

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15
Q

Optical infinity

A
  • object/image ray is collimated
  • object/image may be far away
  • the ray bundle may be collimated by an optical element
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16
Q

Virtual object for a plus lens

A
  • more convergence after the lens.

- if vergence was +5 and lens power is +15, new vergence is +20

17
Q

Virtual object for a minus lens

A
  • vergence is less after the lens.

- vergence seems so be zero (rays become parallel)

18
Q

Images from a plane mirror

A
  • virtual(behind the mirror)
  • equal magnification (1)
  • erect(maintains same vertical orientation)
19
Q

Magnification for a plane mirror

A

-(xi/xo)

MIND THE GAP

20
Q

What is the most prominent shape in optics?

A

-circle is easiest, but ellipse is more prominent

21
Q

radius of curvature for single spherical reflecting surface

A

R to the right, +(convex)
R to the left, -(concave)
“where is the light coming from?”

22
Q

Plane mirror vergence

A
  • DOES NOT CHANGE VERGENCE OF THE BEAM, JUST DIRECTION

- power is optical element that determines vergence, and this is zero

23
Q

Vergence of single spherical reflecting surface

A

negative power, reflected beam has POSITIVE vergence from zero vergence entrance beam

Positive power, reflected beam has NEGATIVE vergence from zero vergence entrance beam

24
Q

Optical power and focal length of a spherical mirror

A

P=-1/f=-2/R

MIND THE GAP

25
Q

Focal length of spherical mirror

A
  • always half the radius of curvature
  • has same sign as R
  • positive to the right, negative to the left
26
Q

Mirror optical power

A

concave-positive OP(parallel beam converges)
Convex-negative OP(parallel beam diverges)
Plane-zero OP(remains parallel)

27
Q

Left facing refractive surface

A

light propagates left to right

28
Q

Spherical mirror imaging equations

A

Xo+P=-Xi
1/xo+(-1/f)=(-1/xi)

MIND THE GAP FOR IMAGE

object beam vergence+ mirror OP=NEGATIVE image beam vergence

29
Q

3 rays for convex surfaces

A
  1. ray parallel to optical axis is REFLECTED as if it originated from focus
  2. ray targeting the focus becomes parallel in reflection
  3. ray that crosses the mirror center of curvature is RETRO REFLECTED
30
Q

3 rays for concave surfaces

A
  1. ray parallel with optical axis is reflected backward towards the focus
  2. ray passing through the focus after reflection becomes parallel
  3. ray that crosses the mirror center of curvature is RETRO REFLECTED
31
Q

Imaging from a convex mirror

A
  • always virtual (space behind mirror)
  • always erect
  • always smaller than object(M
32
Q

Imaging from a concave mirror when object is at distance GREATER than the focal

A
  • real, inverted, located in front of mirror
  • image and object are in same location if xo=2f
  • in every other case, it can be larger or smaller
33
Q

imaging from a concave mirror when object is at distance LESS than the focal

A
  • virtual
  • erect
  • magnified
  • located behind the mirror
34
Q

virtual object for minus lens

A
  • object placed after the optical element
  • positive XO
  • usually is it “to be formed” by another optical element
  • the reason the object is not formed is that along the ray formation path, another element is inserted

Optics Block 2 (3 decks)

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