Waves and reflection general knowledge Flashcards
A pulse
A single disturbance that is propagated through a medium which has an amplitude and pulse length
Amplitude
The distance from the equilibrium position to the highest displacement point (crest or trough)
Equilibrium position
The position at which the medium is at rest
Transverse pulse
A pulse in which the particles of the medium travel in right angles to the propagation direction of the pulse
Interference
The phenomena that occurs when two pulses meet as they move through the same medium
Constructive interference
Occurs when pulses overlap and the resultant displacement of the medium increases at the point of overlap
Destructive interference
Occurs when pulses with displacements in opposite directions overlap and the resultant displacement of the medium decreases at the point of overlap
A medium
The material through which a pulse or wave is propagated
Equilibrium position
The starting point of the wave, when no disturbance is present.
Wavelength
Lambda
The straight line distance between two adjacent points on a wave that are in phase.
Crest and Trough
Highest and lowest (Greatest points on both sides of the equilibrium position) point of the waves displacement.
Frequency (f)
The number of wave crests or troughs that pass a certain point (observer) in a second.
Hz= s^-1
f=1/T
Period (T)
The time taken for a wave to pass a certain point
Seconds= s
T=1/f
What is the wavelength range of visible light?
~400 nm- ~700 nm
Red= ~700 nm
Violet= ~400 nm
The wavelength range of Gamma rays
10^-2 nm to 10^-6 nm
=1 Angstrom
The wavelength range of x- rays
10^-1 nm - 10 nm
The wavelength range of ultraviolet light
100 nm - 10^3 nm
(=1 micrometer)
The wavelength range of infrared light
10 micrometers - 1 mm
The wavelength range of microwaves
1 cm - 1 m
The wave length range of radio waves
10 m - 100 Mm
What is the law of reflection?
The angle of incidence is equal to the angle of refraction
Properties of images formed in plane mirrors
Real image:
- Can be projected onto a screen
- Light rays pass through the image
- Usually inverted
Virtual image:
- Cannot be projected onto a screen
- No light rays pass through the image
- Always upright
What is diffuse reflection?
- Light reflected off rough surfaces
2. Results in scattered rays which give a blurred image.
What is specular reflection?
- Light reflected off smooth surfaces
2. Results in clear, sharp image
Multiple reflection equation
(360/ the angle between the mirror)-1
What would happen if two plane mirrors are placed parallel to one another?
An infinite number of images will be formed
Label the 10 variables involved with curved mirrors
F= focal point I= image size P= pole of axis R= radius of curvature f= focal length O= object size u= image distance v= image distance C= centre of curvature M= magnification
What is LOST?
L- Location
O- orientation
S- size
T- type
Real image
- Can be projected onto a screen
2. Light rays pass through the image
Virtual image
- Cannot be projected onto a screen
2. No light rays pass through the image
What is the sign convention of curved mirrors?
Real is positive.
OR
Virtual is negative.
What is spherical aberration
- Light rays that strike the outer edges of a spherical mirror do not reflect through the focal point
- Leads to blurring of image
- Correction= concave mirrors are shaped as parabolas
- The PARABOLIC REFLECTOR produce a sharp, clear image exactly at the focal point.
Use of parabolic reflectors in everyday life?
- DSTV dish is shaped as a parabola
