Mineralogy: Quiz 3

Front 1

What is the velocity of light in a vacuum in m/s? In nm/s?

Back 1

3 x 10^8 m/s
3 x 10^17 nm/s

Front 2

Velocity of light is _______ dependent.

Back 2

density dependent

Front 3

What is the index of refraction formula?

Back 3

n = velocity vacuum / velocity medium

Front 4

n values increase with _______ .

Back 4

density

Front 5

Light that has a single wavelength.

Back 5

monochromatic light

Front 6

Light that has multiple wavelengths.

Back 6

polychromatic light

Front 7

Electric and magnetic vectors vibrate at ________ angles to each other.

Back 7

right angles

Front 8

Frequency formula?

Back 8

f = v / λ

Front 9

In what kind of materials is the velocity of light the same in all directions?

Back 9

isotropic materials

Front 10

In what kind of materials is the velocity of light varied with direction?

Back 10

anisotropic materials

Front 11

Anisotropic minerals are all chystal classes except __________.

Back 11

isometric

Front 12

angle of incidence = ____________

Back 12

angle of reflection

Front 13

angle of reflection = _____________

Back 13

angle of incidence

Front 14

The amount of light reflected increases with the _____________.

Back 14

angle of incidence

Front 15

When light is bent when passing from one material to another.

Back 15

refraction

Front 16

There is no refraction if light enters ___________ to the surface.

Back 16

perpendicular

Front 17

What is Snell's Law?

Back 17

sinθ1 / sinθ2 = n1 / n2
sinθ1 = angle of incidence
sinθ2 = angle of refraction

Front 18

When light passes from higher n to lower n, light is refracted _______ from the normal.

Back 18

away

Front 19

When light passes from lower n to higher n, light is refracted ________ the normal.

Back 19

toward

Front 20

When the angle of incidence equals 90゜then it is called what?

Back 20

critical angle

Front 21

n depends on ___________ of light transmitted.

Back 21

wavelength (λ)

Front 22

n is higher for ________ λ.

Back 22

shorter

Front 23

n is lower for _________ λ.

Back 23

longer

Front 24

Name the 5 anisotropic crystal classes.

Back 24

1) tetragonal 2) hexagonal 3) orthorhombic 4) monoclinic 5) triclinic

Front 25

n varies with direction through the _____________.

Back 25

crystal lattice

Front 26

What 2 crystal classes are uniaxial anisotropic?

Back 26

1) hexagonal 2) tetragonal

Front 27

What 3 crystal classes are biaxial anisotropic?

Back 27

1) orthorhombic 2) monoclinic 3) triclinic

Front 28

Minerals having one optic axis.

Back 28

uniaxial

Front 29

Minerals having two optic axes.

Back 29

biaxial

Front 30

Waves are said to be "in phase" if they are how many wavelengths apart?

Back 30

1 or more whole numbers

Front 31

Waves are said to be "out-of-phase" if they are how many wavelengths apart?

Back 31

1/2 or any half-lengths

Front 32

When waves reach the upper analyzer in a petrographic microscope and they cancel out each other.

Back 32

in phase

Front 33

In an Michel-Levy birefringence chart, how far apart are the color "orders" in nm?

Back 33

550 nm

Front 34

As temperature increases, λ gets _______.

Back 34

shorter

Front 35

What is the n value of air?

Back 35

n = 1.0003

Front 36

What is the n value of water?

Back 36

n = 1.33

Front 37

n value ________ as density of material increases.

Back 37

increases

Front 38

All visible light is _____________.

Back 38

polychromatic

Front 39

Photons vibrate at ______ angles to the propagation direction.

Back 39

right angles

Front 40

The movement of light or how many waves pass over some interval of time.

Back 40

frequency (f)

Front 41

Wave-to-wave line; time elapsed between two successive troughs/crests.

Back 41

period

Front 42

Shorter wavelengths have _________ frequency.

Back 42

higher

Front 43

Radio waves have ______ frequency.

Back 43

low

Front 44

Cosmic waves have ______ frequency.

Back 44

high

Front 45

A geometric description of a plane perpendicular to the ray in most conditions.

Back 45

wave front

Front 46

A line perpendicular to a plane.

Back 46

normal

Front 47

The angle between the incoming wave and normal to a surface.

Back 47

angle of incidence

Front 48

Red light is _______ refractive.

Back 48

less

Front 49

Violet light is _____ refractive.

Back 49

more

Front 50

When wavelengths enter at different angles they are really entering at different __________.

Back 50

velocities

Front 51

The difference between fast and slow waves.

Back 51

retardation

Front 52

Double refraction is also called ___________.

Back 52

birefringence

Front 53

When light travels through one polarizer its is ___________.

Back 53

plane-polarized

Front 54

The Bertrand lens is used to view _________.

Back 54

interference figures

Front 55

The direction in which the light ray is travelling.

Back 55

propagation direction or ray path

Front 56

What is perpendicular to the ray path?

Back 56

vibration direction

Front 57

Intensity of light.

Back 57

amplitude

Front 58

The speed of light through a mineral will vary as a function of ___________.

Back 58

orientation

Front 59

Covalently-bonded solids will generally have _________ refractive indices.

Back 59

higher

Front 60

Ionically-bonded solids will generally have ________ refractive indices.

Back 60

lower

Front 61

What is the electromagnetic spectrum?

Back 61

the range of all possible electromagnetic radiation frequencies

Front 62

Into what categories is the spectrum typically subdivided?

Back 62

radio waves, infrared, visible light, ultraviolet, gamma, cosmic

Front 63

In what part of the electromagnetic spectrum (wavelength) does visible light fall?

Back 63

between 700 nm and 400 nm

Front 64

What is the difference between ‘red’ and ‘blue’ light?

Back 64

'Red' light is shorter, while 'blue' light is longer.

Front 65

What is the difference between the ‘near’ and ‘far’ end of the electromagnetic spectrum?

Back 65

The 'near' end has shorter wavelengths while the far end has longer.

Front 66

What controls the velocity of electromagnetic radiation in matter?

Back 66

density

Front 67

How does atomic bonding affect n values?

Back 67

Electric and magnetic fields interact with atoms magnetic and electric fields.

Front 68

What are typical n values for the vast majority of minerals?

Back 68

n =1.5 to 2

Front 69

In optical mineralogy, is it more useful to think of light as a wave or as particles?

Back 69

as waves

Front 70

Into what two components can a wave of light be divided?

Back 70

magnetic and electric fields

Front 71

Is the behavior of light in a mineral more a function of the magnetic or electric components of a light wave?

Back 71

electric components

Front 72

What are typical examples of isotropic materials?

Back 72

glass

Front 73

What are typical examples of anisotropic materials?

Back 73

most minerals

Front 74

Why does calcite exhibit double refraction?

Back 74

The beams of light are polarized at right angles to each other.

Front 75

One ray following the ray path in birefringence.

Back 75

ordinary ray

Front 76

The ray that does not follow the ray path in birefringence.

Back 76

extraordinary ray