Section C Waves And Sound Flashcards
(21 cards)
What is wavelength on a sound wave graph?
The distance from one peak to the next.
How do you measure the wave speed?
Wave speed = frequency x wavelength
Which wave has the shortest wavelength?
Gamma.
Which wave has the longest wavelength?
Radio.
Give a use for gamma rays.
Sterilising food and medical equipment.
What are radio waves used for?
Communications.
What are microwaves used for?
Satellite communication and to heat up food (by absorbing water molecules).
What are infrared radiation waves used for?
Hearing and to monitor temperature.
What is visible light used for?
Photography.
What are UV rays used for?
Fluorescent lamps (which are safe because the waves are absorbed by a phosphor coating).
What is a use for X Rays?
They let us see the internal structure of objects and materials.
What is a danger of microwaves?
They can heat human body tissue.
What is a danger of infrared waves?
Can burn skin.
What is a danger of UV Rays?
Damage surface (skin) cells and cause blindness.
What is a danger of gamma rays?
Cell mutation (tissue damage leading to cancer).
What is the law of reflection?
Angle of Incidence = Angle of Reflection
What is meant by total internal reflection?
When light is incident at a boundary between materials at an angle greater than the critical angle, causing light to be reflected back at the boundary.
What is the critical angle for a boundary?
The angle of incidence such that the angle of refraction is 90°.
What is the equation for finding the refracted angle?
n = sin i/ sin r
What is meant by refraction?
When a wave changes direction when it changes speed.
What is dispersion?
When white light is shone through a prism and is separated by colours.
