Chap 5 - reflection, refraction, diffraction, critical, total internal reflection, light drawing, lens Flashcards
define refraction
-change in direction of wave as they pass through different mediums
define reflection
-wave bounces off a plane surface at the same angle it came from
define diffraction
-bending at the ends of a wave as it passes through a narrow gap
define plane surface
2D flat surface
define normal
perpendicular line from the surface
does the wave speed, frequency and wavelength change in reflection
no for all
rays in reflection
-incident
-reflected
rays in refraction in order
-incident
-refracted
is there a normal in refraction and reflection
yes
does the wave speed, frequency and wavelength change in refraction
- f is constant
-v & λ changes
what happens when incident ray is 0 (at normal) for reflection & refraction
-no reflection/ refraction happens
does the wave speed, frequency and wavelength change in diffraction
no change to all
how does size of wave length affect how wave is diffracted
-short wave length, less diffraction
virtual lines in reflection
-distance from obj to mirror is same as distance from virtual image to mirror
-virtual image lines are dotted
-the reflected ray and dotted lines meet
change in v & λ from deep to shallow water
-deep - shallow = v & λ decrease
-f is constant
properties of light
-form of radiation
-travels in straight lines
-transfers energy
-travels as waves
-travels through vacuum
-3 x 10^8 m/s
define luminous & eg
-produce light
-sun, lamp, torch
define non- luminous & eg
-reflect light
-moon, pen, book …
diff of light in white & black
-white reflects all colours
-black absorbs all colours
experiment to know light travels in a straight line
-light through a hole in a dark room
-if light not travel in straight lines = room would be lit
define monochromatic light
-light of a single λ & 1 colour
why are some colours visible
-the colour is reflected while the other colours are absorbed
refraction from less dense medium to more dense medium ( n )
-LDTN
-decrease speed - towards normal
refraction from more dense medium from less dense medium ( n )
-MDAN
-increase speed - away from normal
how to show a surface is a mirror
-hatched lines behind the line
-all rays behind mirror are virtual
define critical angle
-when the refracted ray is perpendicular to normal
-varies with medium
define total internal reflection
-when incident angle is greater than critical angle, there is not refraction - only reflection
-in transparent medium
- has to be from more n to less n & incident angle is more than C
how is diffraction affected by size of gap
bigger gap = decreased diffraction
why do radio waves diffract more than light waves
they have longer wavelengths
what happens when incident angle is more than critical angle
-total internal reflection
-no refraction - only reflection