12: Superposition

Question 1

Define principle of superposition

Answer 1

Principle of superposition states that when two or more waves of the same kind(transverse/longitudinal) meet, the resultant displacement at any point is equal to the vector sum of the individual displacement of the component waves at any point at that instant.

Question 2

Define Coherence

Answer 2

Coherence refers to waves/sources which have constant phase difference

Question 3

Define Stationary Wave

Answer 3

A stationary wave is a result of superposition of two waves of equal amplitude and frequency travelling with the same speed but in opposite directions

Question 4

Define diffraction

Answer 4

Diffraction is the spreading of waves when they pass through an ape rapture or around an obstacle

Question 5

Define interference

Answer 5

Interference is the result of superposition of wave trains from a finite number of coherent sources

Question 6

Equation for young’s double slit + assumption

Answer 6

X = (lamda x D)/a

X - fringe separation
lamda - wavelength
D - distance between double slit and screen
a - slit separation

assumption - monochromatic light must be used if not there might be overlapping spectrums

Question 7

Equation for single slit diffraction

Answer 7

sin x = lamda/b

x - angle between central maximum and first minima
lamda - wavelength
b - slit width

Question 8

What if slits become bigger?

Answer 8

Maxima gets bigger
Minima remains dark as usual

Question 9

Define Resolution (Rayleigh Condition)

Answer 9

Two sources are just resolved when teh central maxima of one diffraction pattern falls on the first minima of the second diffraction pattern

Question 10

Equation for diffraction grating

Answer 10

sin x = (lamda x n)/d

x - angle between central maxima and nth maxima
n - 1,2,3,4…
d = 1m/Number of slits