Light and Optics

Question 0

An observer looking 42° up and away from rain may see a rainbow created from the wavelengths splitting apart as white light travels through the raindrops. What is the term for this phenomenon?

Answer 0

Dispersion - white light incident to face of prism comes out with split wavelengths, because wavelength related to index of refraction, where a small λ has a large n and a smaller angle of refraction when passing into a denser medium

Question 1

The index of refraction (n) is equal to c/v and it is dependent on λ, because c = λf. What are some assumptions to be made from the aforementioned information?

Answer 1

Light of different wavelengths have different speeds and refract at different angles in different media.

Question 2

Speed of Light

Answer 2

Measured in a vacuum, it is 3.00 X 10^8 m/s, where c=λf

Question 3

Snell’s Law

Answer 3

Equation used to find either n or angle of refraction when passing from one medium to another: n1sinθ1=n2sinθ2

Question 4

How does light reach the end of fiber optic cables without really showing up on the sides of the cables?

Answer 4

Total internal reflection occurs when the θ of light traveling from high n to low n is greater than the critical angle: n2/n1=sinθ1

Question 5

Law of Reflection

Answer 5

θi = θr

Question 6

Pointing a flashlight through a small slit leads to a spreading out effect called?

Answer 6

Diffraction, where there are bright and dark fringes. The dark fringes could be located with: a sinθ = nλ

Question 7

How do polarizing sunglasses work?

Answer 7

The polarizing filters on the sunglasses only allow electromagnetic waves parallel to the filter through, leading to plane-polarized light and preventing glare from hitting the eyes.

Question 8

Virtual Image

Answer 8

An image produced at a point where light does not actually converge.

Question 9

Real Image

Answer 9

Image produced at a point where light actually converges.

Question 10

Lens Makers’ Equation

Answer 10

1/f = 1/p + 1/q

Question 11

Magnification

Answer 11

m = -i/o

A negative value means that the image is inverted.

Question 12

What is the term for the distance between the focal point and the mirror or lens?

Answer 12

Focal Length

Question 13

What type of mirror is your bathroom mirror and what type of image does it produce?

Answer 13

Assuming you have a normal bathroom mirror, it is a plane mirror where the incident light rays remain parallel after reflection. A plane mirror always produces a virtual image the same distance behind the mirror as the object is in front of the mirror.

Question 14

Spherical Mirror

Answer 14

Curved mirror with a focal length equal to r/2.

Question 15

What type of mirror is the make-up/ shaving mirror?

Answer 15

It is a converging mirror, which is concave, with a positive focal length. Beyond the focal point, an object in front of the converging mirror produces a virtual image. At the focal point, no image occurs. Before the focal point, an object produces a real image.

Question 16

Diverging Mirror

Answer 16

A convex mirror that has a negative focal length and that always leads to virtual images.

Question 17

Converging Lens

Answer 17

A thick-centered lens that converges light rays at a single point. An object beyond the focal point will produce a real, inverted image. Placed before the focal point, the object produces a real, upright image. The virtual side is on the same side as the object for lenses.

Question 18

Diverging Lens

Answer 18

A thin-centered lens that always produces a virtual image.

Question 19

Wavelengths (Å) of Spectrum

Answer 19

UV < 4000
Violet 4000 - 4250
Blue 4250 - 4900
Green 4900 - 5750
Yellow 5750 - 5850
Orange 5850 - 6500
Red 6500 - 7000
Infrared > 7000

Question 20

What type of lenses does the eye have?

Answer 20

Lenses in contact, where the equivalent focal length follows this equation: 1/f = Σ1/f

Question 21

What type of lens configuration are in telescopes and microscopes?

Answer 21

Lenses not in contact, where the magnification of the system involves multiplying the magnification of all of the individual lenses.

Question 22

Monochromatic Light

Answer 22

Light of only one wavelength

Question 23

Coherent Light

Answer 23

Light waves whose phase differences do not change with time

Question 24

Interference

Answer 24

Amplitudes if light waves sum up

Question 25

Electromagnetic Waves

Answer 25

A transverse wave with a magnetic field and electric field perpendicular to each other

Question 26

Photon

Answer 26

It is an electric and magnetic wave perpendicular to each other and perpendicular to the direction of propagation.

Question 27

Moving from a medium of low index of refraction to a medium with a higher index of refraction causes light to:

Answer 27

Slow down and bend towards the normal

Question 28

Fermat’s Principle

Answer 28

Light takes the fastest path between two points.

Question 29

Energy of Photon

Answer 29

E = hf