Interference and Diffraction

Question 1

Diffraction

Answer 1

Where a wave hits a gap or an obstacle and spreads out

Question 2

When wavelength > gap, the is a _______ amount of diffraction

Answer 2

Large

Question 3

When wavelength < gap, the is a _______ amount of diffraction

Answer 3

Small

Question 4

Features of a single slit diffraction graph

Answer 4

• Symmetrical
• Central maxima double the width of of the smaller maxima
• Smaller maxima all have the same width

Question 5

Monochromatic light

Answer 5

All has the same wavelength

Question 6

Coherent waves

Answer 6

Have the same frequency and wavelength, and have a constant phase difference

Question 7

How can light be made coherant

Answer 7

Passing it through a single slit

Question 8

Path difference

Answer 8

The difference in the length of the paths of two waves meeting at a point (measured in wavelengths)

Question 9

Conditions for Young’s double split experiment

Answer 9

Coherent light sources

Question 10

Results of Young’s double slit experiment (monochromatic)

Answer 10

Interference pattern of equally spaced bands of light and dark which get less intense further from the center

Question 11

Results of Young’s double slit experiment (white light)

Answer 11

Interference pattern of equally spaced bands of light and dark which get less intense further from the center.
Central maximum is white, the fringes either side show a spectrum.