waves

Question 1

2 points for progressive wave (2)

Answer 1

• transfers energy from one point to another

- w/o transferring material

Question 2

2 points for describe motion of particle on transverse wave (2)

Answer 2

• oscillates

- about equilibrium position perpendicular to centre

Question 3

amplitude wave definition (2)

Answer 3

• MAXIMUM displacement

- from equilibrium position

Question 4

if wave superpose and knot on one wave becomes motionless where is knot

Answer 4

at node (destructive interference)

Question 5

what waves are transfers

Answer 5

surface of water/water waves/in ripple tank (1)
rope (1)
slinky clearly qualified as transverse (1)
secondary (‘s’) waves (1)

Question 6

example use polarising filters and why

Answer 6

polaroid sunglasses reduced glare

or 3D glasses = enhance viewing

Question 7

3 ways to increase fundamental frequency of string (1)

Answer 7

• increase tension

- tighten string

Question 8

when talking about path wave always say

Answer 8

returns to equilibrium

Question 9

for describe nature longtidunal (2)

Answer 9

oscillation PARTICLES parallelo to direction of WAVE travel

Question 10

is light transverse

Answer 10

yes

Question 11

is ultrasound transverse

Answer 11

yes (can be longitudinal in fluids) but stick w/ transverse

Question 12

The sound quality of a portable radio is improved by adjusting the orientation of the aerial.
Which statement is a correct explanation of this improvement?

Answer 12

radio waves from transmitter are polarised

Question 13

relation sound wavelength and light wavelength

Answer 13

sound wavelength > light wavelength

Question 14

how does polarisation provide evidence for transverse waves

Answer 14

Polarisation provides ​evidence for the nature of transverse waves​ because polarisation can only occur if a wave’s oscillations are perpendicular to its direction of travel (as they are in transverse waves).

Question 15

for tube when in antiphase wavelengths are at

Answer 15

quietest

Question 16

6 marker on stationary wave formations

Answer 16

(1) a wave and its reflection / waves travelling in opposite directions
meet / interact / overlap / cross / pass through etc
point (1)
• (2) same wavelength (or frequency)
• (3) node − point of minimum or no disturbance
points (3) may come from a diagram but only if the node is written in full and the y-axis is labelled amplitude or displacement
• (4) antinode − is a point of maximum amplitude
point (4) may come from a diagram but only if the antinode is written in full and the y-axis is labelled amplitude or displacement
• (5) node - two waves (always) cancel / destructive interference / 180° phase difference / in antiphase [out of phase is not enough] (of the two waves at the node) [not peak meets trough]
• (6) antinode − reinforcement / constructive interference occurs / (displacements) in phase
• (7) mention of superposition [not superimpose] of the two waves
• (8) energy is not transferred (along in a standing wave).

Question 17

what to always say in stationary wave at end fo 6 marker

Answer 17

energy is not transferred along standing wave

Question 18

what can be said for nodes

Answer 18

180 degree phase difference apart

Question 19

for stationary wave when superpose always same

Answer 19

same wavelength and freq

Question 20

if motionless

Answer 20

stationary wave formed (explain process if 3 marker on motionless knot)

Question 21

how to make second harmonic ( adjust for others) on an instrument (2)

Answer 21

lightly) stop (in centre)
pluck or bow

Question 22

to increase / decrease fundmental frequency how to derive

Answer 22

from equation

Question 23

what can be said about the space between 2 adjacent nodes on a stationary wave

Answer 23

particles rope oscillate in phase

Question 24

for a stationary wave what can be said about particles immediately on either side of node

Answer 24

moving in opposite directions

Question 25

conditions for stationary wave

Answer 25

same frequency/wavelength not ‘it has same frequency’ moving in opposite directions, reflected at end of string, same/similar amplitude integer no of ½ wavelengths between walls

Question 26

difference progressive and stationary in energy transfer

Answer 26

progressive wave, energy is transferred through space (1) | stationary wave, energy is not transferred through space (1)

Question 27

difference progressive stationary in amplitude

Answer 27

each point along wave (1) has same amplitude for progressive wave but varies for stationary wave (1)

Question 28

diff P + S in phase

Answer 28

progressive wave, adjacent points vibrate with different phase (1) stationary wave, between nodes all particles vibrate in phase [or there are only two phases] (1)

Question 29

how are stationary waves produced

Answer 29

superposition (of progressive waves) incident wave and reflected wave/wave reflected through 180O/waves travelling in opposite directions same frequency/wavelength in same medium.

Question 30

for stationary wave have to say at fixed

Answer 30

END not ends

Question 31

how to calculate value for speed transverse wave usage signal generator set up

Answer 31

frequency read from signal generator when standing wave produced / use of strobe etc. measure λ using several loops or full length of string node → node / each loop = λ / 2 use of c = fλ

Question 32

sunglasses depend on light

Answer 32

polarised when reflected from surface

Question 33

comparing motion 2 nodes on stationary string

Answer 33

similar freq amplitude and speed ( or pi radians out of phase)

Question 34

using larger tensions = __ Frequency

Answer 34

reduce diameter w/ increasing tensions = lower mass per unit length therefore greater frequency --> every metre has a Lower mass

Question 35

in tension freq length equation what does relationship between 2 variables depend upon

Answer 35

other variables being constant - if not constant then explain why values may be diff using equation

Question 36

increase diameter by 2

Answer 36

mass increases by 4 (4 x thicker due to square)

Question 37

if it asks for steps taken by scientific COMMUNITY

Answer 37

-results published -method checked repeatable ( community = once published)

Question 38

safety precautions taken while measuring diffraction grating

Answer 38

- don't look in laser beam | - avoid possibility reflected laser beam

Question 39

3 points on why only transverse waves polarised (3)

Answer 39

- displacement vector perpendicular to energy travel (transverse) - longitudinal parallel - polarisation restriction displacement vector to 1 plane

Question 40

why can only specific frequency stationary waves form on wire

Answer 40

as fixed ends have to be nodes

Question 41

what happens to unpolarised EM wave passing through polariser

Answer 41

intensity reduced ( by exactly 1/2)

Question 42

3 conditions for stationary wave

Answer 42

Same speed Moving in opposite directions same wavelength / same frequency/ similar amplitudes 