12.3 +12.4 Young's double slit experiment, stationary waves

Question 1

what does mono-chromatic mean?

Answer 1

all the waves emmited are of the same frequeny (colour)

Question 2

describe why young had this set up

Answer 2

• filter: monochromatic
• single slit : diffraction would produce a coherant wave, producing a stable interference pattern

Question 3

what do the fringes suggest?

Answer 3

bright fringes:
* contructive interference
* light waves arrive in phase

dark:
* deconstructive interference
* light waves arrive in anti phase

Question 4

what is the equation from young’s slit experiement?

Answer 4

Question 5

what is a stationary wave?

Answer 5

a wave that oscillates in time but does not transfer any (net energy)

Question 6

how are stationary waves formed?

Answer 6

two progressive waves of same frequency propagate in opposite directions and superpose

only certain frequnecies will produce stationary waves (harmonic)

Question 7

what is the amplitude of a stationary wave for a single point?

Answer 7

• constant at all times time

Question 8

what is a node?

Answer 8

a point of zero displacement

distnace between 2 adjacent nodes =half λ

Question 9

what is an anti node?

Answer 9

a point of maximum displacement

Question 10

what is the phase difference between 2 adjacent nodes/ anti nodes ?

Answer 10

0

Question 11

what is the phase difference between either side of a node ?

Answer 11

π (180 degrees)

Question 12

what is the phase difference between all points between adjacent nodes?

Answer 12

0- they are all inphase, as they all reach maximum displacement together

Question 13

do stationary waves transfer energy?

Answer 13

yes, but not tot heir surroundings

Question 14

how are nodes and anti nodes created in a stationary wave?

Answer 14

between two progressive waves (same frequnecy ) travelling in opposite directions:
* destructive interference, (180 phase difference) = node
* constructive interefence,(0 phase diference) = anti node

Question 15

what is the difference between the definition of ‘wavelength’ for the two different waves?

Answer 15

• progressive wave: distance between 2 adjacent points oscillating in phase
• stationary wave: twice distance between adjacent nodes = wavelength of 2 progressive waves (OG) that made the stationary

Question 16

what is the difference between the definition of ‘phase difference’ for the two different waves?

Answer 16

• progressive wave: the phase chnages across one complete cycle of waves
• stationary waves: all parts of the wave between a pair of nodes are in phase and on different sides of a node they are in anti phase

Question 17

what is the difference between the definition of ‘amplitude’ for the two different waves?

Answer 17

• progressive wave: all parts of the wave that have the same amplitude
• stationary wave: maximum amplitude occurs at the anti node then drops to zero at the node

Question 18

What type of wave is a stationary wave?

Answer 18

Can be transverse OR Longitudinal (formed by longitudinal waves such as sound waves ), depending on the type of original wave that formed it

Question 19

What are some differences between stationary and progressive waves ?

Answer 19

Progressive: all points have the same amplitude
Stationary: points have different amplitudes (nodes have zero amplitude)