Reflection, Speed, Wavelength and Frequency Flashcards
Sound waves and light waves change speed when…
They pass across the boundary between two substances with different densities such as air and glass. This caused them to change direction is this is called a refraction
Refraction doesn’t happen if the waves cross the boundary at what angle
90 degrees
Laboratory way of measuring speed of sound.
A loud speaker is connected to a signal generator and two microphones are plugged in to an input of a duel beam oscilloscope. The oscilloscope can measure the time taken for sound to reach the microphones.
Outside way of measuring the speed of sound.
Stand 40m in front of a tall building and bang two blocks of wood together. Each time you hear an echo bang the blocks together again and time how long it took to hear echo’s
Formula for wavelength of one wave
Wavelength = length/number of waves
Formula to calculate wave speed
Wave speed = Frequency * wavelength
What is a virtual wave?
An image formed by light rays which appear to diverge from a point
Example: When waves change speed as they pass from one medium to another.
2 types of lenses
Concave
Convex
Types of waves in the electromagnetic spectrum
10 (3) 10 (-2) 10 (-5) 10 (-6) 10 (-8) 10 (-10) 10 (-12)
10 (3) Radio 10 (-2) Micro 10 (-5) Infrared 10 (-6) Visible Light 10 (-8) UV 10 (-10) X-Rays 10 (-12) Gamma Rays
When light travels through a prism, a rainbow is created, this is called…
Why does this happen?
Waves change speed as they pass from one medium to another
A hot object will emit more/less radiation
An object will begin to glow red when it reaches 500/1000 degrees
More
1000 degrees
What is total internal reflection
When light crosses materials with different refractive indicies, the light beam will be bent at the boundary surface at the critical angle.
Why is light refracted through a glass block
The light is refracted because the speed of light in glass is different to the speed of light in air, it changes direction towards the normal when it leaves the glass as light is faster in air than glass. It is caused by waves changing speed as they pass from one medium to another.
Why are gamma and ultraviolet rays dangerous?
The higher the frequency of the radiation the more damage it can do (cancer).
What are some uses for electromagnetic waves?
Communication (TV, Radio), heating, highlighters, medical things
How are EM waves produced?
Electrical signal (bottom) Transmitting Area (top) Magnetic Forces (first wave) Electric forces (2nd/3rd Wave) Direction of travel (up and down) Receiving electrical signal (at the end)
Labels on a ripple tank
Wave peak: the difference between two waves
Wave generator: first line at the start
Trough: Middle between two waves
Low Amplitude
High Amplitude
Low Pitch
High Pitch
Low Amplitude: Low Wave Height
High Amplitude: High Wave Height
Low Pitch: Low number of waves
High Pitch: High number of waves
Diagram of a transverse wave
Normal line: Line across the middle Peak/Crest: Highest point of the wave Direction of the wave is sideways Particles are moving up and down Trough: Lowest point of the wave Amplitude: Lowest/Highest point on the wave to the normal line.
Ray diagram of reflection
Incident ray: the ray before hitting the mirror
AO incidence: the angle of the incident ray to the normal.
Normal: the line perpendicular to the mirror
Reflected ray: The ray after hitting the mirror
AO reflection: The angle of the reflected ray to the normal
Law of reflection: AO Incidence = AO reflection
Drawing a ray diagram
Normal Line: Line perpendicular to Glass Block
Incident Ray: Ray going into the glass block
Refraction: Inside the glass
Refracted ray: Ray coming out the glass.
