Interference

Question 1

Principle of superposition

Answer 1

When two or more waves overlap, the resultant amplitude is the vector sum of individual amplitudes

Question 2

Stationary waves

Answer 2

Formed by the superposition of two waves traveling in opposite directions with the same frequency and amplitude

Question 3

Nodes

Answer 3

Points of zero displacement in a stationary wave

Question 4

Antinodes

Answer 4

Points of maximum displacement in a stationary wave

Question 5

Diffraction

Answer 5

The spreading of waves when they pass through a gap or around an obstacle

Question 6

Factors affecting diffraction

Answer 6

Greater when gap width is similar to or smaller than the wavelength

Question 7

Interference

Answer 7

The superposition of two or more waves to form a resultant wave of greater, lower, or the same amplitude

Question 8

Coherence

Answer 8

Two waves are coherent if they have a constant phase difference and the same frequency

Question 9

Conditions for two-source interference

Answer 9

Sources must be coherent and produce waves of similar amplitude

Question 10

Double-slit formula
λ = ax/D

Answer 10

Wavelength (λ) = (slit separation (a) * fringe separation (x) ) / distance from splits to screen (D)

Question 11

Diffraction grating equation
d sin θ = nλ

Answer 11

d sin θ = nλ
d (grating spacing) * sin θ (angle of diffraction) = n (order of diffraction) * λ (wavelength)

Question 12

Grating Spacing (d)

Answer 12

d = 1/N
where N is the number of slits per meter