revision unit 7

Question 1

what are transverse waves

Answer 1

they are waves that there oscillations are perpendicular to the direction of energy transfer, all electromagnetic waves are transverse waves.

Question 2

what are longitudinal waves

Answer 2

they are waves that there oscillations are parallel to the direction of energy transfer, they constant of rarefactions and compressions, sound wave is an example of longitudinal waves

Question 3

what is amplitude

Answer 3

the height of the wave crest, the bigger the amplitude the more energy the waves carry

Question 4

what is the wave length

Answer 4

the distance from one crest to the next crest

Question 5

what is the frequency

Answer 5

it is the number of times a wave crest has passed trough a fixed point very second

Question 6

what is wave speed

Answer 6

wave speed = frequency x wavelength

Question 7

what are wave fronts

Answer 7

the waves travelling across the water surface

Question 8

explain how reflection happens in wave fronts the are parallel to the barrier

Answer 8

as the incident ray approach the barrier it would be parallel to the barrier and once it gets reflected it would still stay parallel

Question 9

explain how reflection happens in wave fronts the are not parallel to the barrier

Answer 9

when each wave front reaches the the barrier, it creates a wavelet moving away from the barrier at the same angle as the rest of the wavelets would line up with it forming a wave front.

Question 10

what is refraction

Answer 10

it is the change of direction of travel of waves when they cross boundary from one medium to another

Question 11

explain what happens when waves cross a boundary

Answer 11

when a the wave front reaches the boundary would slow down as the wavelet change direction, when the other wavelets reach the boundary they would line up with the other wavelet that has crossed forming a wave front

Question 12

what is diffraction

Answer 12

it is the spreading of waves when they pass through a gap or past an obstacle, the narrow the gap the more they spread-out

Question 13

what are examples of diffraction

Answer 13

1. the diffraction of light in a Hubble space, where small amount of diffraction happens because its wide to see clear and detailed picture
2. the diffraction of ultrasound waves where we would not have a narrow transmitter in order not to have the image too faint because of the waves spreading out to much

Question 14

why might there be single problems at hilly areas

Answer 14

because when the radio waves come trough they the s would be diffracted above the hill and not reach under the hill making the signal not reach the mast