Waves

Level 2 Physics External

the law of _______ states that θ_i = θr

reflection

angles (θ) are measured against the _______

normal

the ______ is a line perpendicular to the surface

normal

the _______ is the reflection of a physical ______ in a mirror

image, object

the image of reflection is the same ______ from the mirror as the object

distance

the nature of an image in a plane mirror is:

• ________ (upright/inverted)

• ________ (the same/a different) distance as the object from the mirror

• laterally _______

• ________ (diminished/the same size/enlarged)

• _______ (virtual/real)

upright, the same, inverted, the same size, virtual

a _______ image can be projected onto a screen

real

a _______ image cannot be projected onto a screen

virtual

what is the letter/symbol used for radius of curvature?

R

what is the letter/symbol used for focal point?

f

the _______ ______ is where reflected rays converge

focal point

the relationship between focal point and radius of curvature is R = ___

2f

the point of radius of curvature is represented by _ on a diagram

c

the horizontal centre line on a ray diagram is called the _______ axis

principle

the vertical centre line on a ray diagram is called the ______ axis

optical

a concave mirror is _________ (converging/diverging)

converging

a convex mirror is _________ (converging/diverging)

diverging

a concave lens is _________ (converging/diverging)

diverging

a convex lens is _________ (converging/diverging)

converging

ray 1 enters a mirror ______, and exits ______ (parallel/through focal point)

parallel, through focal point

ray 2 enters a mirror ______, and exits ______ (parallel/through focal point)

through focal point, parallel

ray 3 is reflected from the pole according to the _____ __ _______

law of reflection

the intersection between the optical and principle axes is called the ______

pole

a ______ image is formed in front of the mirror while a ______ image is formed behind the mir

the nature of an image reflected in a concave mirror from an object beyond the focal point is:

• ________ (real/virtual)

• ________ (upright/inverted)

• ________ (diminished/enlarged)

real, inverted, diminished

the nature of an image reflected in a concave mirror from an object inside the focal point is:

• ________ (real/virtual)

• ________ (upright/inverted)

• ________ (diminished/enlarged)

virtual, upright, enlarged

an image reflected in a concave mirror from an object __ the focal point cannot be formed, as there is no point where light _______

at, converges

the nature of an image reflected in a convex mirror is:

• ________ (real/virtual)

• ________ (upright/inverted)

• ________ (diminished/enlarged)

virtual, upright, diminished

the mirror-lens formula is 1/f = 1/d_o + 1/d_i

• if d_i is on the real side of the mirror, it is a ______ value; if on the virtual side, it is a ______ value

• a concave mirror has a _______ f value; a convex mirror has a _______ f value

positive, negative, positive, negative

the formula for magnification is m = d_i/d_o = h_i/h_o

• magnification is an ______ value, so always positive. if negative in the calculation, image created is virtual

• if m = _, then the object and image are the same size; if m > 1, then the image is ______; if m < 1, then the image is ______

• if inverted, the height is _______

absolute, 1, enlarged, diminished, negative

in the mirror-lens formula, the units must all be the _____

same

an image formed on the opposite side of a lens from the object is _____

real

the near focal point is closer to the ______, while the far focal point is closer to the ______

object, image

ray 1 enters a convex lens ______, and exits ______ (parallel/through near focal point/through far focal point)

parallel, through far focal point

ray 2 enters a convex lens ______, and exits ______ (parallel/through near focal point/through far focal point)

through near focal point, parallel

ray 3 travels _______ through the pole, without being refracted

straight

the nature of an image refracted through a convex lens from an object inside the focal point is:

• ________ (real/virtual)

• ________ (upright/inverted)

• ________ (diminished/enlarged)

virtual, upright, enlarged

the nature of an image refracted through a convex lens from an object beyond the focal point is:

• ________ (real/virtual)

• ________ (upright/inverted)

• ________ (diminished/enlarged)

real, inverted, enlarged

the nature of an image refracted through a concave lens is:

• ________ (real/virtual)

• ________ (upright/inverted)

• ________ (diminished/enlarged)

virtual, upright, diminished

ray 1 enters a concave lens ______, and exits ______ (parallel/through near focal point/through far focal point)

parallel, through near focal point

ray 2 enters a concave lens ______, and exits ______ (parallel/through near focal point/through far focal point)

through far focal point, parallel

______ is the bending of a wave as it moves from one medium to another of different density

refraction

waves change ______ in different optical densities, causing them to ______

speed, bend

when light travels into a denser medium, it _____ ___ (slows down/speeds up) and it bends ______ ___ (closer to/away from) the normal

slows down, closer to

when light travels into a less dense medium, it _____ ___ (slows down/speeds up) and it bends ______ ___ (closer to/away from) the normal

speeds up, away from

the _____ of refraction, _, is a measure of the difference in ________ between two different media, based on their _______ ______

index, n, wavespeed, optical density

n_medium = c/v, where:

• c is the speed of light in a ______ (constant)

• v is the speed of light within the _______

vacuum, medium

n_air = _, where v = c

1

n ≥ _

1

a _____ magnitude for n will cause a wave to slow down more

large

snell’s law is n₁sinθ₁ = n₂sinθ₂, where θ is always measured in ________

degrees

______ _______ _______ occurs when a light ray is unable to pass through a boundary, so there is no refracted ray and it is instead totally reflected off the boundary into original medium

total internal reflection

t.i.r. requires a ray of light to be travelling into a _____ optically dense medium at θ_i ≥ θ_{_____}

less, critical

the ______ angle is specific to the medium

critical

for snell’s law at the _____ angle, is n₁sinθ_c = n₂sinθ₉₀, where sinθ_c = n₂ / n₁

critical

in _______ waves, wave particles move perpendicular to the direction of energy travel

transverse

in _______ waves, wave particles move parallel to the direction of energy travel

longitudinal

do electromagnetic or mechanical waves require a vibrating medium?

mechanical

________ waves are created by the interactions between vibrating electric and magnetic fields, without any physical ______ vibrating

electromagnetic, particles

what is the letter/symbol used for period?

T

what is the letter/symbol used for frequency?

f

what is the letter/symbol used for wavespeed?

v

what unit is represented by the symbol λ?

wavelength

period is measured in _______, _

seconds, s

frequency is measured in __

Hz

wavespeed is measured in ____

m/s

wavelength is measured in ______, _

metres, m

what is the letter/symbol used for amplitude?

A

amplitude is measured in _______, _

metres, m

frequency and period are _______ proportional, where f = 1/T

inversely

radio waves have the _______ wavelength, _______ frequency and _______ energy

longest, lowest, lowest

gamma rays have the _______ wavelength, _______ frequency and _______ energy

shortest, highest, highest

radio waves, microwaves, infrared waves, visible light and some UV waves are all examples of ________ radiation

non-ionising

some UV waves, x-rays and gamma rays are all examples of ______ radiation

ionising

in a _______ (or air), the speed of all _______ waves is the same at 3.0 × 10⁸ m/s

vacuum, electromagnetic

a wavefront meeting a boundary at an angle changes ________ due to ________

direction, refraction

waves change speed when entering a different ______ or when changing ______

medium, depth

waves travel _______ in deep water and _______ in shallow water

faster, slower

as waves move into shallow water, its bends _______ (towards/away from) normal. the: (increases/decreases/stays the same)

• wavelength ________

• frequency _______

• wave speed ________

• amplitude _______

towards, decreases, stays the same, decreases, increases

______ is the spreading out of a wavefront as it passes through a ____ or around an ______

diffraction, gap, obstacle

light does not diffract as easily as sound or water as it has a ______ wavelength

shorter

diffraction causes the speed, wavelength and frequency to _______ (increase/decrease/stay the same)

stay the same

diffraction is at a maximum when the wavelength is _______ (higher than/lower than/equal to) the gap size

equal to

______ (shorter/longer) wavelengths diffract more

longer

antinodes are formed by ________ (constructive/destructive) interference. waves from each gap arrive _______ (in phase/out of phase) with a path difference of ___λ (n/n+½). the waves ______ (reinforce/cancel out) and make a ______ (bright/dark) spot

constructive, in phase, n, reinforce, bright

______ are points of constructive interference

antinodes

nodes are formed by ________ (constructive/destructive) interference. waves from each gap arrive _______ (in phase/out of phase) with a path difference of ___λ (n/n+½). the waves ______ (reinforce/cancel out) and make a ______ (bright/dark) spot

destructive, out of phase, n+½, cancel out, dark

______ are points of destructive interference

nodes

if wavelength decreases, antinodal lines become ______ (closer together/further apart); eg, _____ (red/blue) to _____ (red/blue) light

closer together, red, blue

________ of waves occurs when waves add together when meeting at a point, and _______ patterns occur

superposition, interference

a _______ is a single wave travelling through a medium

pulse

when a pulse is travelling from a fast to slow medium, the reflected pulse is ______, transmitted pulse is ______

inverted, upright

when a pulse is travelling from a slow to fast medium, the reflected pulse is ______, transmitted pulse is ______

upright, upright

when a pulse is changing between mediums, both the reflected and transmitted pulses have a ______ (larger/smaller) amplitude

smaller

a pulse has a _____ edge

leading