P11 - waves

Question 1

what are mechanical waves

Answer 1

waves that travel through a medium

Question 2

examples of mechanical waves

Answer 2

sound waves, water waves, seismic waves

Question 3

what are electromagnetic waves

Answer 3

waves that travel through a vacuum and don’t require a medium

Question 4

examples of electromagnetic waves

Answer 4

light waves, radio waves and micro waves

Question 5

does the substance move when waves travel through it (does the water move when an object is dropped in it

Answer 5

no, waves travel across the surface but the water does not travel away from the object.

Question 6

what type of waves are electromagnetic waves

Answer 6

transverse waves

Question 7

where are the oscillations in relation to direction of energy transfer on a transverse wave

Answer 7

perpendicular

Question 8

what type of waves can mechanical waves be

Answer 8

both transverse and longitudinal

Question 9

where are the oscillations in relation to direction of energy transfer on a longitudinal wave

Answer 9

parallel.

Question 10

what type of waves are sound waves

Answer 10

longitudinal

Question 11

how do sound waves work

Answer 11

when an object vibrates on the air, it makes the air around it vibrate as it pushes and pulls through the air. These oscillations (compressions and rarefactions) are sound waves

Question 12

what is amplitude

Answer 12

maximum displacement of a wave from its undisturbed position (from the middle to the top of the wave)

Question 13

what is the trough

Answer 13

the bottom of the wave

Question 14

what is the peak/crest

Answer 14

the top of the wave

Question 15

what is the wavelength

Answer 15

the distance between 2 same points of the wave (peak to peak)

Question 16

what does amplitude show

Answer 16

the bigger the amplitude the more energy a wave has

Question 17

what is the frequency

Answer 17

the number of waves passing a fixed point in a second

Question 18

what is a peroid

Answer 18

the time taken for the wave to pass a fixed point in a second.

Question 19

what is the equation for peroid

Answer 19

peroid,t (sec) = 1 / frequency(Hz)

Question 20

what is the equation for wavespeed

Answer 20

wave speed ,v m/s = frequency, f Hz x wavelength m

Question 21

what is the speed of waves

Answer 21

the distance travelled by each wave every second through a medium.

Question 22

why do we see things from far away before we hear them

Answer 22

speed of light is quicker than the speed of sound.

Question 23

what are plane waves

Answer 23

straight waves`

Question 24

what is refraction

Answer 24

where waves change the direction they travel when they cross boundary between one medium and another

Question 25

what is an incident wave

Answer 25

the initial wave

Question 26

what happens to waves at a non zero angle to the boundary

Answer 26

the waves change their speed and direction when they cross the boundary

Question 27

what happens to waves at a perpendicular boundary

Answer 27

the waves do not change direction however their speed changes.

Question 28

what happens to the amplitude of waves when they pass through a substance

Answer 28

it gets smaller as the substance absorbs some of the energy.

Question 29

what is the speed of sound waves in air

Answer 29

340m/s at 15 degrees.

Question 30

what is an echo

Answer 30

reflected sound

Question 31

what is the equation for the time of an echo

Answer 31

speed,s = distance to wall and back, 2d / time, t

Question 32

can sound waves travel through a vacuum

Answer 32

no

Question 33

how do you investigate waves

Answer 33

use a ripple tank for water waves
a stretched string for waves in a solid
a signal generator and a loud speaker for sound waves