Physics 5 - Waves and Optics

Question 1

transverse wave?

Answer 1

displaces up and down

Question 2

longitudinal wave

Answer 2

<–>

Question 3

wave velocity equation?

Answer 3

v=f*λv= velocity, f=frequency,λ=wavelength

Question 4

definition of wavelength?

Answer 4

distance from any point where wave repeats itself

Question 5

definition of frequency?

Answer 5

of wavelengths that pass a fixed point per secondUnits: Hzdetermined by SOURCE

Question 6

definition of period?

Answer 6

reciprocal of frequency, it is time taken for wave to move 1λdetermined by SOURCE

Question 7

wave velocity depends on

Answer 7

medium density and medium inertia

Question 8

relative velocities of sound?

Answer 8

Sold>liquid>gas

Question 9

decibels(dB)

Answer 9

log scale, for increase of 10 dB, add another exponentEx: 10-30 dB = 100 fold increase(10^3)

Question 10

what is resonance?

Answer 10

when natural frequency and driving frequency match. = max vibration and max amplitude

Question 11

what is pitch?

Answer 11

correlates to frequency, higher pitch=higher freq.

Question 12

what is an antinode?

Answer 12

area of max displacement. found in standing waves/causes string to vibrate at natural/resonant frequency

Question 13

what is attenuation/damping?

Answer 13

causes decrease in freq and velocity. results in decreased intensity of wave

Question 14

Doppler Effect

Answer 14

change in perceived frequency when wave source and observer are moving. together = higher f, further=lower f

Question 15

doppler equation

Answer 15

observed freq=Source freq.*(C±Vo)/(C±VS)Δfreq/source freq=v/c andΔλ/λsource=v/cwhere v is relative speed of source/observer and c is speed of wave in the mediumobserved freq=source freq±Δfreq or λo=λs±Δλif moving closer together, add source freq andΔfreq or subtractΔλ fromλs

Question 16

in what direction does a moving photon (light) displace the E field and Magnetic field?

Answer 16

perpendicularly to eachother

Question 17

equation for energy of a photon?

Answer 17

E=hfdirectly proportional to its frequencyh is Planck’s constant 6.64e-34

Question 18

visible light range (in nm?)

Answer 18

390nm-700nm

Question 19

visual spectrum?

Answer 19

infrared ROYGBIV ultravioletlongerλ<–> shorter λ

Question 20

what is the speed of light?

Answer 20

3e8 m/s (usually represented by c)

Question 21

definition of reflection?

Answer 21

light/wave bounces back at angle = to angle of incidence

Question 22

definition of refraction?

Answer 22

when light/wave bends towards the normal

Question 23

what is index of refraction?

Answer 23

n=c/vdetermines how light travels through the medium

Question 24

snell’s law?

Answer 24

n1sintheta=n2sintheta2

Question 25

what is dispersion?

Answer 25

when all light scatters

Question 26

what is diffraction?

Answer 26

light/wave bends around an object

Question 27

what is the focal point?

Answer 27

where real or virtual light rays converge

Question 28

what is focal length?

Answer 28

distance between mirror/lens and focal point=1/2 radius of curvature

Question 29

equation for lens power?

Answer 29

determined by  focal length, P=1/f units: diopters: m-1

Question 30

what does a converging mirror/lens do?

Answer 30

reflects light to converge at point in front of mirror/opposite lens

Question 31

what is a diverging mirror/lens?

Answer 31

reflects light so perceived image is on opposite side of mirror/lens from observer

Question 32

converging lens/mirror characteristics?

Answer 32

real, inverted, on the same side, and +"I am positive that the image is real and inverted

Question 33

diverging mirror/lens characteristics?

Answer 33

virtual, upright, opposite, and (-)

Question 34

special object distance rules for convergers?

Answer 34

if object d> focal point: image is real invertedif object d

Question 35

thin lens equation?

Answer 35

1/f=1/do+1/di

Question 36

virtual images always have _ sign

Answer 36

negative

Question 37

real images always have a _ sign

Answer 37

positive

Question 38

converging lens always have a _ focal length sign

Answer 38

positive

Question 39

diverging lenses always have a _ focal length sign

Answer 39

negative

Question 40

the object distance is positive when

Answer 40

it is on the "right side"

Question 41

what is the sign for a real image distance?

Answer 41

positive

Question 42

what is the sign for a virtual image distance?

Answer 42

negative

Question 43

equation for magnification?

Answer 43

M= -di/do=hi/hofor multiple lens systems, magnification is multiplicative

Question 44

the lower the index of refraction the ___ light travels

Answer 44

faster

Question 45

what is hyperopia? and how is it corrected

Answer 45

farsightedness, corrected with converging lens

Question 46

what are the harmonics for a pipe closed at one end?

Answer 46

all odd numbered

Question 47

sound waves are ____ waves

Answer 47

longitudinal

Question 48

the resolution for imaging techniques is proportional to

Answer 48

wavelength, (shorter is better)

Question 49

what happens to the refractive index as freq. increases?

Answer 49

refractive index also increases

Question 50

according to snells law, as n2 increases, sintheta2 must

Answer 50

DECREASE

Question 51

what does a lower index of refraction do to the refraction angle?

Answer 51

inversely proportional according to snell's law. so large refraction angle results from LOW index of refraction

Question 52

shortest period = shortest____

Answer 52

wavelength

Question 53

what is total internal reflection?

Answer 53

when light wave has angle of incidence greater than the critical angle

Question 54

what is happening to particles in a longitudinal wave?

Answer 54

they are striking eachother to propogate the wave

Question 55

what is the equation for frequency of a spring?

Answer 55

f=(1/2pi)*(sqrt(k)/m)

Question 56

what is the potential energy of a spring?

Answer 56

PE=1/2k*deltax2

Question 57

what is the wavelength of a standing wave in a closed-closed or open open space?

Answer 57

lambda=2L/nwhere L is length and n is harmonic

Question 58

T/F, photon speed is influenced by their energy

Answer 58

FALSE

Question 59

what do you need to utilize the doppler equation?

Answer 59

one of the speeds (detector or source), along with the observed and emitted frequencies

Question 60

the intensity of EM radiation is directly proportional to

Answer 60

number of photons emitted

Question 61

what is the equation for magnification?

Answer 61

di/do

Question 62

how do you calculate the energy of a photon released from an excited electron?

Answer 62

subtract lower energy level from excited energy level

Question 63

what does a decrease in bending do to the focal length?

Answer 63

increases it

Question 64

how do you figure out the higher harmonic frequencies?

Answer 64

they are multiples of the fundamental frequency, so f2=2*f1

Question 65

a negative focal length indicates

Answer 65

DIVERGING lens

Question 66

what is the fundamental frequency of a vibrating string?

Answer 66

f=v/2L

Question 67

what kind of lens is required by nearsighted people?

Answer 67

diverging, because the focal length is too short and the image is focused in front of the retina

Question 68

what is a plane mirror?

Answer 68

produces image behind its plane at distance equal to object distance in front of the plane.