Ch 8 - Lights and Optics Flashcards

1
Q

What are electromagnetic waves?

A

transverse waves that consist of an oscillating electric field and an oscillating magnetic field
- the 2 fields are perpendicular to each other and to the direction of propagation of the wave
c = f x lambda

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2
Q

What is the electromagnetic spectrum?

A
  • the range of frequencies and wavelengths found in EM waves

- from lowest to highest: radio, microwaves, infrared, visible light, UV, xray, and gamma

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3
Q

What wavelength does the visible spectrum run from?

A

approximately 400 nm (violet) to 700 nm (red)

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4
Q

WHat is reflection?

A

the rebounding of incident light waves at the boundary og a medium

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5
Q

What is the law reflection?

A

states that the incident angle will equal the angle of reflection, as measured from the normal

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6
Q

What are the components of a spherical mirror?

A

they have centers and radii of curvature and focal points

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7
Q

What are concave mirrors?

A
  • converging systems and can produce real, inverted images or virtual, upright images, depending on the placmeent of the object relative to the focal point
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8
Q

What is a convex mirror?

A

diverging systems and will only produce virtual, upright images

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9
Q

What are plane mirrors?

A
  • produce virtual, upright images
  • these images are always the same size as the object
  • may be thought of as sperical mirrors with infinite radii of curvature
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10
Q

What is refraction?

A

the bending of light as it passes from one medium to another

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11
Q

What does changes in the speed of light depend on and what causes refraction?

A
  • depends on index of refraction of the medium

- change in speed of light causes refraction

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12
Q

What causes dispersion of light through a prism?

A

the behavior of the amount of refraction depends on the wavelength of the light invovled

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13
Q

What is Snell’s law?

A

(the law of refraction)
- states that there is an inverse relationship between the index of regraction and the sine of the angle of refraction (measured from the normal)
n = c/v
n1 = sin(angle1) = n2sin(angle2)

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14
Q

When does the total internal reflection occur?

A

when light cannot be refracted out of a medium and is instead reflected back inside the medium
- this happens when light moves from one medium with a higher index of refraction to a medium with a lower inde of refraction with a high incident angle
angle = sin -1 (n2/n1)

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15
Q

What is the critical angle?

A

the minimum incident angle at which total internal reflection occurs

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16
Q

What do lenses do?

A

refract light to form images of objects

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17
Q

Where are the focal points on thin symmetrical lenses?

A

on each side

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18
Q

What is the difference between convex and concave lenses?

A
  • convex: converging systems and can produce real, inverted images or virtual, upright images
  • concave: diverging systems and will onoly produce virtual, upright images
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19
Q

What do lenses with non negligible thickness require?

A

use of the lensmaker’s equation

1/f - (n-1)(1/r1 - 1/r2)

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20
Q

When do converging systems create real, inverted images?

A

when o > 2f, o = 2f, 2f > o > f

21
Q

When are the real, inverted images of converging systems different?

A
  • o > 2f: reduced
  • 0 = 2f: same
  • 2f > o > f: magnified
22
Q

When do converging systems form no image?

A

when o = f

23
Q

When do converging systems form virtual images?

A

o < f

virtual, upright, magnified

24
Q

What type of images do diverging systems form?

A

virutal, upright, reduced for all object distances

25
Q

What is diffraction?

A

the bending and spreading out of light waves as they pass through a narrow slit
- may produce a large central light fringe surroinded by alternating light and dark fringes with the addition of a lens

26
Q

What does interference support?

A

the wave theory of light

27
Q

What does Young’s double slit experiment show?

A

the constructive and destructive interference of waves that occur as light passes through parallel slits, resulting in minima (dark fringes) and maxima (bright fringes) of intensity

28
Q

What happens in plane-polarized light?

A

all the light rays have electric fields with parallel orientation

29
Q

How is plane polarized light created?

A

by passing unpolarized light through a polarizer

30
Q

What happens in circulatory polarized light?

A

all of the light rays have electric fields with equal intensity but constantly rotating direction

31
Q

How are circularly polarized light created?

A

exposing unpolarized light to special pigments or filters

32
Q

What is the order of colors in the visible spectrum?

A

ROY G BV

red, orange, yellow, green, blue, violet

33
Q

What follows the same trend as the electromagnetic wave? What is opposite?

A

frequency has the same trend, wavelent is the opposite

34
Q

How are the 4 distances of mirrors related?

A

1/f = 1/o + 1/i = 2/r

35
Q

What is magnification and how is it calculated?

A

a dimensionless value that is the ratio of th eimage distance to the object distance
m = -i/o
if |m| < 1: image is smaller than object (reduced)
if |m| > 1: image larger than object (enlarged)
if |m| = 1: image same size as object

36
Q

Where is the image any time an object is at the focal point of a converging mirror?

A

the reflected rays will be paralle so the image will be at infinity

37
Q

How do you find the image in mirrors?

A
  • draw the rays and find where the lines intersect
  • ray parallel to axis reflects back through focal point
  • ray through focal point reflects back to axis
  • ray to center of mirror reflects back at same angle relative to normal
38
Q

How do the focal lenghts compare between converging and diverging mirrors/lenses?

A
  • converging: always positive

- diverging: always negative

39
Q

Assumine o is positive, what are the image types possible with a single lens or mirror?

A

UV NO IR

  • Upright images are always Virutal
  • No inage is formed when object is focal length away
  • Inverted images are always Real
40
Q

What happens to light when it enters a medium with a higher v lower index of refraction?

A
  • higher: bends towards the normal

- lower: it bends away from normal

41
Q

How do you find the image in lenses?

A
  • draw the rays and find where the lines intersect
  • ray parallel to axis refracts through focal point of fornt face of lens
  • ray through or toward focal point before reaching lens refracts parallel to axis
  • ray to center of lens continues straight through with no refraction
42
Q

In mirrors, is the sign convention for o, i, r, f, and m?

A
  • +o: object is in front of mirror; -o: object is behind mirror (extremely rare)
  • +i: image is in front of mirror (real); -i: image is behind mirror (virtual)
  • +r/+f: mirror is concave (converging); -r/-f: mirror is convex (diverging)
  • +m: image is upright (erect); -m: iamge is inverted
43
Q

In lenses, is the sign convention for o, i, r, f, and m?

A
  • +o: object is on same side of lens as light source; -o: object is on opposite side (extremely rare)
  • +i: image is on opposite side of lens (real); -i: image is on same side (virtual)
  • +r/+f: lens is convex (converging); -r/-f: lens is concave (diverging)
  • +m: image is upright (erect); -m: iamge is inverted
44
Q

How is power calculated?

A

P = 1/f (diopters)

45
Q

How is the location of the the dark fringes (minima) given?

A

a x sin(angle) = n x lambda

46
Q

How does the diffraction pattern for a single slit differ from a slit within a thin lens?

A
  • diffraction through a single slit does not create characteristic fringes when projected on a screen, although the light does spread out
  • when a lens is introduced into the system, the additional refraction of light causes constructive and destructive interference, creating fringes
47
Q

What wave phenomenon do diffraction fringes result from?

A

fringes result from constructive and destructive interference between light rays

48
Q

How does double slit diffraction and interference differ from single-slit diffracton?

A
  • the image formed during double slit contains fringes because light rays constructively and destructively interfere
  • a single slit forms an image of a wide band of light, spread out from its orignial beam