Wave Motion (16)

Question 1

Mechanical Waves

Answer 1

• require a medium to travel through

- disrupt the medium physically

Question 2

Electromagnetic Waves

Answer 2

• Do not require a medium to travel through

- cause electric and magnetic disruption

Question 3

travelling waves

Answer 3

• carry energy away from its source through a medium without any overall movement of the medium

Question 4

longitudinal waves

Answer 4

• the direction of vibration is parallel to the direction in which the wave is travelling

Question 5

transversal waves

Answer 5

• the direction of vibration is perpendicular to the direction in which the wave is travelling
• all EM waves

Question 6

Wavelength

Answer 6

• length of a complete cycle
• antinode to antinode (crest to crest) or node to node (transversal)
• compression to compression/rarefaction to rarefaction (longitudinal)
• λ
• metres

Question 7

Amplitude

Answer 7

• the maximum displacement from the mean position

- the distance between the base line and the crest/trough

Question 8

Frequency

Answer 8

• number of vibrations per second
• f
• Hz

Question 9

Speed

Answer 9

• speed at which the wave propagates through the medium
• c
• m/s

Question 10

Period

Answer 10

• time taken for the cycle to occur
• T
• seconds
• T = 1/f

Question 11

wave formula

Answer 11

c = f λ

Question 12

reflection

Answer 12

the bouncing of a wave off an object

Question 13

Refraction

Answer 13

the bending of a wave as passes from one medium to another and changes speed

Question 14

Diffraction

Answer 14

the spreading out of a wave as it moves through a gap or around an obstacle

Question 15

interference

Answer 15

when waves combine to form a resultant amplitude which is made up of each waves individual amplitude

Question 16

constructive interference

Answer 16

when waves combine to form a resultant amplitude greater than each individual waves amplitude

Question 17

destructive interference

Answer 17

when waves combine to form a resultant amplitude smaller than each individual waves interference

Question 18

coherant waves

Answer 18

two waves that are in step or a fixed amount out of step which produce an interference pattern

Question 19

in phase

Answer 19

causes constructive interference

Question 20

180° out of phase

Answer 20

causes destructive interference

Question 21

polarisation

Answer 21

a wave is confined to a particular plane

Question 22

stationary waves

Answer 22

waves of the same frequency and amplitude that constructively and destructively interfere to produce a wave pattern in a confined space

Question 23

doppler effect

Answer 23

• the apparent change in frequency due to the relative motion of source and observer
• higher apparent frequency when moving towards a person
• lower apparent frequency when moving away

Question 24

node

Answer 24

the minimum displacement of a wave from its base level

Question 25

antinode

Answer 25

the maximum displacement of a wave from its base level

Question 26

Red and Blue shift

Answer 26

• low frequency is red (moving away)
• high frequency is blue (moving towards)
• used to measure the velocity of stars