8. Superposition

Question 1

principle of superposition

Answer 1

when two or more waves meet at a point,
resultant displacement is the sum of the individual displacements.

Question 2

experiments that demonstrate stationary waves

Answer 2

microwaves, stretched
strings and air columns

Question 3

formation of a stationary wave

Answer 3

waves travel along string and reflect at fixed point/wall/end/vibrator generator. incident and reflected waves superpose.

Question 4

graphical method, and identify nodes and antinodes

Answer 4

node- zero amplitude- 180 degree phase in stationary waves if a node is in between

Question 5

diffraction

Answer 5

1.wave passes through/by/around an edge/apeture.
2. wave spreads into geometrical shadow.

Question 6

experiments that demonstrate diffraction

Answer 6

gap width relative to the wavelength of the wave

Question 7

interference and coherence

Answer 7

coherent- constant phase difference between the waves with time.

Question 8

experiments that demonstrate two-source interference

Answer 8

water waves in a ripple tank, sound, light and microwaves

Question 9

conditions required if two-source interference fringes are to be observed

Question 10

double-slit interference using light- formula

Answer 10

1. light diffracts at the two slits.
2. light from each slit meets/superpose at the screen.
3. when the phase difference is 0 degrees a bright fringe/ intensity maximum is formed.
4. when the phase difference is 180 degrees a dark fringe/ intensity minimum is formed.

λ = ax /D
wavelength= slit sep*fringe sep/distance from screen to double slit.

Question 11

diffraction grating

use of a diffraction grating to determine the wavelength of light

Answer 11

dsinθ = nλ

d-
sinθ-
n-
λ