P14 - Light

Question 1

reflection

Answer 1

-plan wave reflects from a flat barrier

Question 2

reflected waves are

Answer 2

at same angle to barier as incident wave

Question 3

when wavefront reaches barrier =

Answer 3

wavelet moving away

Question 4

all parts of waefront

Answer 4

move at the same speed

Question 5

reflected and incident rays are

Answer 5

same frequency, speed, wavelength

Question 6

law of reflection

Answer 6

normal is perpendicular to mirror
- incident angle = reflected angle
-light reflected by plane mirror

Question 7

specular reflection

Answer 7

reflection in a single direction without scattering

Question 8

diffuse reflection

Answer 8

from a rough surface that scatters light

Question 9

image formed by a plane mirror =

Answer 9

virtual image
-upright
-laterally inverted

Question 10

virtual images are formed

Answer 10

at a place where light rays appear to come from after they have been reflected

Question 11

real image

Answer 11

seen on a screen
-formed by focusing light onto a screen

Question 12

refraction

Answer 12

change in direction of waves when they travel across a boundary
-change mediums

Question 13

change of speed =

Answer 13

change of direction

Question 14

light travels from air to glass

Answer 14

-bends towards normal
- smaller angle of refraction
-more dense medium

Question 15

light travels from glass to air

Answer 15

away from the normal
-larger angle of refraction
-less dense medium

Question 16

stars and lamps

Answer 16

• emit light that has a range of wavelengths (white light)

Question 17

lasers

Answer 17

narrow range of wavelengths

Question 18

violet to red (visible light spec)

Answer 18

-increases wavelength of light

Question 19

colour filters

Answer 19

absorbs every colour of light’s wavelength except its own
-transmits its own

Question 20

colour of surface depends on

Answer 20

pigments in surface materials + wavelengths of light the pigments absorb

Question 21

pigments reflect

Answer 21

other wavelengths

Question 22

a red book in blue light look

Answer 22

black
- absorbs all incident light

Question 23

transparent

Answer 23

transmit all incident light
- travels through
- no light is absorbed

Question 24

translucent

Answer 24

• let light pass but light is scattered/refracted
• as material has lots of internal boundaries = changes direction of rays

Question 25

opaque

Answer 25

-absorbs all light
- reflected/scattered at the surface