physics topic 3

Question 1

How do waves transfer energy

Answer 1

without transferring matter

Question 2

What are waves caused by

Answer 2

oscillations

Question 3

what are the two types of waves

Answer 3

Longitudinal and transverse waves

Question 4

how are oscillations formed in longitudinal waves

Answer 4

the oscillations are parallel to the direction of energy transfer. this causes compressions and refractions

Question 5

what is an example of a longitudinal wave

Answer 5

a sound wave

Question 6

how are oscillations formed in transverse waves

Answer 6

the oscillations are perpendicular to the direction of energy transfer. this causes crests and troughs

Question 7

what are examples of transverse waves

Answer 7

light and water waves

Question 8

what is the peak/crest

Answer 8

the highest point on a wave

Question 9

what is the wavelength

Answer 9

the distance from one point on one wave to the identical point on the next wave

Question 10

what is amplitude

Answer 10

the maximum distance of a point on the wave from its rest position

Question 11

what is density

Answer 11

the amount of matter in a given volume

Question 12

how do you calculate the density of a material

Answer 12

mass/volume

Question 13

what happens when waves arrive at a boundary between two different materials

Answer 13

they can be reflected, absorbed or transmitted

Question 14

what is refraction

Answer 14

when the direction of a wave changes because it has changed speed as it has travelled from one medium to another

Question 15

what is meant by the law of reflection

Answer 15

the angle of incidence is always equal to the angle of reflection

Question 16

what is a wave

Answer 16

a disturbance that transfers energy from one place to another

Question 17

what is the medium

Answer 17

the material a wave passes through

Question 18

what are mechanical vs electromagnetic waves

Answer 18

mechanical waves need a medium to transfer energy whereas electromagnetic waves do not

Question 19

what is the frequency

Answer 19

the number of waves that pass a point each second
unit- hertz (Hz)

Question 20

what is the trough

Answer 20

the minimum point of the wave

Question 21

what is the period

Answer 21

the length of time it takes one wave to pass a given point

Question 22

how are volume and pitch measured in sound waves (longitudinal)

Answer 22

how loud a sound is (volume) depends on the amplitude
the pitch depends on the frequency (Hz)- the higher the frequency the higher the pitch

Question 23

what is the frequency range for humans

Answer 23

humans can hear frequencies between 20 and 20000 Hz (anything higher is known as ULTRASOUND)

Question 24

what is the normal

Answer 24

the imaginary line at right angles to a surface

Question 25

what is the velocity

Answer 25

the speed of a wave in the direction it is travelling unit- m/s FORMULAS- velocity= displacement/ time velocity= frequency (Hz) * wavelength (m)

Question 26

how do you calculate the period

Answer 26

period= 1/ frequency (Hz)

Question 27

what happens when light moves from a more dense medium to a less dense medium

Answer 27

it bends away from the normal

Question 28

what happens when a wave enters a new medium

Answer 28

wavelength and speed change but frequency remains constant - when a wave enters a more dense medium the velocity decreases and the wavelength decreases - when a wave enters a less dense medium the velocity increases and the wavelength increases