Superposition

Question 1

what is the principle we need to know about what happens when two or more waves of the same type meet at a point

Answer 1

• the resultant displacement of the oscillations will be the vector sum of their individual displacements
• in other words, the waves combine to form a new wave
• where their oscillations are taken into consideration to form an “average” wave

Question 2

what would an example of a constructive wave be

Answer 2

• two waves of the same type and oscillations meet
• they both have an amplitude of A
• when they meet they form a new larger wave
• with an amplitude of 2A

Question 3

what would an example of a destructive wave be

Answer 3

• two waves of the same type but with polar opposite oscillations meet
• one has an amplitude of A and the other has one of -A
• when they meet they cancel each outer out
• creating a standing wave where there are no oscillations

Question 4

what would be the correct terminology to describe the in sync and out of sync oscillations you can get

Answer 4

• the constructive wave was formed due to the waves being in phase with each other
• the destructive wave was formed due to the waves being in anti-phase with each other

Question 5

how many radians would an antiphase pair of waves be out of sync by

Answer 5

pi radians (180 degrees)

Question 6

what are the in phase waves producing when they combine

Answer 6

a maximum amplitude

Question 7

although the superpositioning of waves can only occur between waves of the same type, what is another condition that needs to be met

Answer 7

• they need to be in the same plane

- so the same type of waves but polarised at right angles to each other cant superposition

Question 8

how does noise cancellation work

Answer 8

• destructive superpositioning is used to nullify the sound waves
• the outside sound is picked up by a microphone and electronically processed
• it is then transmitted to earphones pi radians out of phase