Waves (wave properties - waves for detection and exploration)

Question 1

What is the equation for period

Answer 1

1/frequency

Question 2

what is the equation for wave speed?

Answer 2

frequency x wavelength

Question 3

What are transverse waves?

Answer 3

waves that oscillate perpendicular to the direction of energy transfer

Question 4

what are the longitudinal waves?

Answer 4

waves that oscillate parallel to the direction of energy transfer

Question 5

What is the definition of frequency?

Answer 5

the number of waves passing a fixed point per second

Question 6

what is amplitude?

Answer 6

the maximum displacement that any particle achieve from its undisturbed position

Question 7

what is the wavelength?

Answer 7

the distance from one point on a wave to the equivalent point on the next wave

Question 8

what is a period?

Answer 8

the time taken for one complete oscillation in seconds

Question 9

What do waves transfer?

Answer 9

energy

NOT MATTER

Question 10

what is the relationship between the wavelength and speed?

Answer 10

they are directly proportional

Question 11

What happens when a wave is transmitted from one medium to another

Answer 11

their speed and wavelength changes

frequency stays the same

Question 12

Why does the frequency stay the same when a wave is transmitted from one medium to another?

Answer 12

because the same number of waves is still being produced by the source per second

Question 13

What does the amplitude indicate?

Answer 13

the amount of energy a wave is carrying

the more energy the higher the amplitude

Question 14

When waves reach a boundary between one medium and another, they can be …….

Answer 14

reflected, refracted, absorbed or transmitted

Question 15

What does the direction of refraction depend on?

Answer 15

• the angle at which the wave hits the boundary

- the materials involved

Question 16

what happens when light travels from a material with a low refractive index to one with a higher refractive index?

Answer 16

it bends towards the normal

- slows down

Question 17

high refractive index to low refractive index =

Answer 17

bends away from the normal

- speeds up

Question 18

Refraction is due to ……

Answer 18

difference in the wave speed in the different media

Question 19

What happens when light enters, at an angle, a medium in which it travels slower

Answer 19

• the first part of the light wave to enter the medium slows down
• the rest of the wave continues at the higher speed
• causes the wave to change direction towards the normal

Question 20

what does the amplitude in sound indicate?

Answer 20

its volume

high = loud

Question 21

what does the frequency in sound indicate?

Answer 21

pitch

high frequency = high pitch

Question 22

What is the normal range of human hearing

Answer 22

20hz - 20,000 hz

Question 23

sound is due to …..

Answer 23

the vibration of particles that make up matter

Question 24

sound cant travel in _________

Answer 24

a vacuum

Question 25

Within the ear sound waves causes…

Answer 25

the ear drum and other structures to vibrate- vibration heard as sound

Question 26

what frequency does ultrasound have?

Answer 26

higher than 20,000 hz

Question 27

What happends when ultrasound waves are directed into an object and arrive at a boundry between one material and another?

Answer 27

they will be partially transmitted and partially reflected

Question 28

How do you determine how far way a boundry is?

Answer 28

by measuring the time taken for reflected ultrasonic waves to return to a detector

Question 29

How can ultrasound be used for medical imaging?

Answer 29

1) ultrasound waves pass through the body but when they reach the boundry between two different media ( like fluid in the womb and the kin of the foetus) some of the wave is reflected back and detected
2) the exact timing and distribution of these echoes are processed by the computer to produce a video image of the foetus

Question 30

An example of how ultrasound can be used for industrial imaging

Answer 30

finding flaws in material

Question 31

what is echo sounding (sonar)

Answer 31

the use of ultrasonic waves for detecting objects in deep water and measuring the depth of water

Question 32

Features of P-waves

Answer 32

• logitunidal
• travel at the speed of sound
• twice as fast as s-waves
• travel at different speeds through solids and liquids

Question 33

Features of S-waves

Answer 33

• transverse

- can’t travel through liquids

Question 34

why do seismic waves travel in a curved path through the Earth?

Answer 34

Due to the Earth increasing with density with depth

and when they are refracted they change their speed gradually

Question 35

S- wave shadow zone is due to…

Answer 35

s-waves not being able to travel through the liquid outer core of the earth; provides evidence of the size of the Eath’s core

Question 36

What happens when seismic waves reach a boundary between different layers of material?

Answer 36

some are absorbed, some are refracted

Question 37

P waves shadow zone is due to:

Answer 37

• waves being refracted at the boundary between the semi-solid mantle and the liquid outer core
• waves are refracted again at the boundary between the liquid outer core and solid inner core

Question 38

what are the p- waves shadow zone used to determine?

Answer 38

the size and composition of inner and outer core

Question 39

total internal reflection can only happen when…

Answer 39

the light ray is going from a dense to a less dense medium

Question 40

What happens when the angle of incidence is less than the critical angle?

Answer 40

Most of the light passes (refracted) out but a little bit is internally reflected

Question 41

What happens when the angle of incidence is equal to the critical angle?

Answer 41

the angle of refraction is 90 degrees

Question 42

What happens when the angle of incidence is greater than the critical angle?

Answer 42

no light is refracted and all of the light is internally refracted creating total internal reflection