P5.1 Flashcards
What is a wave?
A wave is an oscillation that transfers energy
What is an electromagnetic wave?
a wave that consists of oscillating electric and magnetic fields
What is a longitudinal wave?
A wave who’s vibration is the same direction of the energy transfer of the waves
What is a mechanical wave?
A wave that requires a medium to travel through
What is the natural frequency?
The frequency at which an object oscillates if it is displaced
What is normal?
A line at 90° to the surface where the wave hits
What is a refraction?
The change in direction of a wave when it’s speed changes as a result of going from one medium to another
What is a sour wave?
A wave produced by a vibration that needs a medium to travel through
What is a transverse wave
A wave whose vibration are at right angles to the direction of transfer energy by the wave
What are vibrations?
The backwards and forwards motion of a solid or particles , displaces from an equilibrium position
What is wave velocity?
The speed at which the energy of a wave is transferred
What is wavelength?
The distance from one point of a wave to the same point on the next wave
Symbol: Lambda
Unit:metres
Amplitude
Distance from the middle to the top or bottom of the wave
Symbol: A
What is frequency?
The number of waves or oscillations per seconds
Symbol:F
Unit: Herz
What is a time period?
The amount of time taken for a wave to pass a given point
Symbol: T
Units: seconds
What are the two ways to represent a wave
A time trace or a snapshot
Time trace- shows how displacement varies with time at a particular position
Snapshot: shows how displace,ent varies with distance
How do you calculate wave velocity?
Wave velocity (m/#) = frequency(Hz) X wavelength(m)
How do you calculate wavelength
Wavelength= wave velocity ➗ frequency
If the velocity increases, and the wave length increases, the frequency will stay the same
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What will happen to a sound wave that hits the boundary at 0°to the brink,
It will speed up but won’t change direction
What happens when a sound wave hits the boundary between two media?
The sound can be:
Reflected ( an echo)
Transmitted
Absorbed
What is ultra sound?
Ultrasound is the sound of a frequency greater 20,000 Hz.
It is useful as it has a small wavelength so you can focus it into a beam
How can you use ultrasound?
Doctors can use ultrasound to find kidney stones and monitor blood flow.
To find distances such as the depth of water:
The transmitter sends an impulse and calculates the distance from the echo
Echo sounding and sonar (Sound navigation and ranging)
What happens when a sound wave hits a solid?
After an echo is reflected many times, the sound is absorbed. This makes the particles in wall vibrate and the wall gets a bit hotter.
How does your ear detect sound?
Your ear is designed to detect, amplify and convert sound to an electric signal.
- The outer ear gathers the sound wave and directs it to the ear drum
- The ear dum vibrates
- The vibration passes to the inner ear through the oval window
The range of frequencies you hear depends on the range of lengths of hair in your cochlea
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