What is the frequency of a wave?
The number of complete cycles of a wave passing a certain point.
True of false? Transverse waves have sideways vibrations?
True
Give 2 examples of longitudinal waves.
Sound waves and P-waves
Calculate the frequency of a wave travelling at 2m/s with a wavelength of 3.5x10^-12
5.71428571x10^11
Give 3 ways you can measure the speed of waves.
1) Using an oscilloscope
2) Water ripples and a strobe light.
3) Using a metal rod, hammer and a microphone connected to a computer
Briefly describe refraction.
Waves Changing Direction at a Boundary
Does the frequency of the wave change at all during refraction?
No.
How do sound waves pass on energy?
Through rarefactions and compressions transferring energy through particles.
What is the frequency of ultrasound?
Higher than 20,000Hz
Give 2 uses of ultrasound.
Medical imaging and Industrial imaging.
What is the frequency of infrasound?
Below 20Hz
Give 2 animals that use infrasound for communication.
Elephants and whales
Give 2 things that cause seismic waves.
Earthquakes and Explosions
Can P-waves travel through the earth’s core?
Yes, S-waves can’t
Describe P-waves
Longitudinal
They travel through solids and liquids
They travel faster than s-waves
Describe S-waves
Transverse
Can only travel through solids
Slower the P-waves
Complete:
Angle of incidence=?
Angle of reflection
What does Total Internal reflection depend on?
The critical angle
If the light ray enters a block at an angle larger than the critical angle, What happens?
No light comes out, it’s all internally reflected
If light is reflected by something rough, does the surface look matted or shiny?
Matted
Why do you need to do the refraction practical in a dim room.
So you can clearly see the ray
Do different materials refract rays at different angles?
Yes, pure glass bends light more than plastic does.
If white light travels through a green filter then a blue filter. What colour will the light be?
No light travels through.
Why are objects different colours?
They reflect different wavelengths of light
Which lens has a virtual Focus Point?
Concave Lens
What does the power of a lens increase with?
The curvature
Give the order of the Electromagnetic Spectrum from highest to lowest frequency.
Gamma, X-rays, UV, Visible, Infrared, Microwaves, Radiowaves
What do all EM waves do?
Transfer energy to their surroundings.
Which colour is the best emitter and absorb-er of EM waves?
Black
Give 2 uses of Radio waves
Communication, broadcasting and used by satelites
Give 2 uses of microwaves
Satellites, microwave ovens
Give 2 uses of Infrared
Increase or monitor temperature, Thermal imaging, transferring information
Give 2 uses of Visible Light
Photographs and illuminating things
Give 2 uses of UV
UV lights, Security pens, Sterilising water.
Give 2 uses of X-rays
Seeing inside things, airport security scanners
Give 2 uses of Gamma rays
Sterilisation, tracers, cancer detection and treatment.