8 - Light and Optics

Question 1

Electromagnetic Wave=

Answer 1

is the traveling oscillation of an electric and a magnetic field.
-Transverse Wave

Question 2

Light=

• *Visible light is from:
• *shorter waves lengths=
• *Longer waves lengths=

Ultraviolet=

Infrared=

Answer 2

is a tiny sliver from the electromagnetic spectrum

.390 - 700 10^-9m

.violet light.

red light

.just beyond violet, and beyond the visible spectrum on the smaller wavelength side.

beyond red, and beyond the visible spectrum on the longer wavelength side.

Question 3

Index of refraction (n)=

*Roy G. Biv —>

*Getting closer to ultraviolet light these wavelengths have

Answer 3

** n =c/v**

acronym for the order of the colors in the visible spectrum
Red, orange, yellow, green, blue, indigo, violet

more energy, this is why ultraviolet rays give you sunburns.

Question 4

Plane-polarized light=

Dual Nature (light)=

Answer 4

if we use a device to screen out all photons not having an electric field in one particular direction, the resulting light with all electric fields oriented in the same direction we have plane-polarized light.

it acts like both a wave and a particle.

• wave theory describes propagation properties of light
• particle theory describes energy transformation properties

Question 5

Angle of incidence=

Angle of reflection=

Angle of refraction=

**Angle of incidence=

Answer 5

the angle at which the light ray strikes the interface.

the angle at which it reflects

the angle at which it refracts.

*angle of incidence = angle of reflection

Question 6

Snell’s Law=

*When light crosses into a new medium, the frequency remains ______ and the wavelength ________.

• if the index of refraction is higher the wavelengths become
• if the index of refraction is lower the wavelengths become

Answer 6

the same, changes

shorter (higher, shorter)

longer (lower, longer)

(n1)(sin [theta1]) = (n2)(sin[theta2])

Question 7

E =

Answer 7

E = hf

Question 8

Total internal reflection=

Critical angle=

Chromatic dispersion=

Answer 8

when light is coming from a medium with a higher index of refraction, the angle of incidence can be so great that the entire amount of photons will be reflected at the angle of reflection, and none will refract.

is the angle at which total internal reflection occurs.

when white light, all the frequencies in the visible spectrum, are split by a prism.

Question 9

Diffraction=

*Constructive interference resulting in
*Destructive interference resulting in

Answer 9

Another type of wave-bending phenomenon.
-smaller the opening the larger the wavelength.

bright bands.

dark bands.

Question 10

Mirrors
Lenses

Answer 10

reflect light

refract light

Question 11

Virtual image=

Real image=

Answer 11

doesn’t not actually exist outside the mind of the observer, no light rays emanate from a virtual image.

exists separately from the observer. Rays of light actually intersect and then emanate from the point of intersection to form a real image.

Question 12

Two types of mirrors:
Two types of lenses:

*trick to remember converging lens: 3 C’s

*thicker center of a lens will
*thinner center will

Answer 12

convex and concave

Diverging (concave) and converging (convex)

thicker

     * *_C_**enter
                      * *_C_**onverges light

converge light

diverge light.

Question 13

Radius of curvature=

Answer 13

a small enough section of any curve can be extended to form a perfect circle. The radius of curvature for that small section of the curve is the radius of the extended circle.

Question 14

Focal Point=

-focal point affected by

Answer 14

light from horizontal rays is reflected by concave mirrors (or refracted by converging lenses) to focus on a single point.

refractive index of the lens, medium of the lens, and the radii of curvature of both sides of the lens.

Question 15

Focal length=

Answer 15

the focal point for any mirror or lens is separated from the mirror or lens by the focal length.

** f (mirror) = (1/2)r**

Question 16

Power=

Answer 16

a measurement of the lens’ strength. Measured in diopters. (inverse of the focal length)

** P = 1/f**

Question 17

Lateral magnification (m)=

-negaitve sign indicates?

Answer 17

is the ratio of the size of the image to the size of the object.

• negative sign indicates that, if both distances are positive, the image is inverted.
• also equal to the negative of the ratio of the distance of the image di and distance of the object do from the mirror or lens.

** m= -di/do = hi/ho**

Question 18

Angular magnification=

Answer 18

another way to measure magnification.

** 1/f = 1/do + 1/di**

Question 19

Two lens system:

Answer 19

M = m1m2

P eff = P1 + P2

Question 20

System for mirrors and lenses:

three steps–>

Answer 20

1) begin by drawing your mirror or lens and an eye on the side on which the observer will stand. “I (eye) am positive that real is inverted” On the side with the eye drawn write “positive, real, inverted”
Opposite of the eye side will be negative, virtual, and upright.

2) Label front back of the mirror or lens. Objects are always positive when they are in front of a lens or a mirror and always negative when they are behind a lens or a mirror.

3) As long as the object is in front, convex mirrors and diverging lenses make negative, virtual, upright images.
AND

As long as the object is in front, concave mirrors and converging lenses make positive, real, inverted images EXCEPT when the object is within the focal distance, in which case they make negative, virtual, upright images.