Interference and diffraction

Question 1

All waves can?

Answer 1

Reflect​, Refract​, Diffract

Question 2

Diffraction in long and short wavelengths

Answer 2

Long wavelengths diffract more than shorter wavelengths​

Question 3

What is interfernce?

Answer 3

When two waves meet they may combine to produce a new pattern

Question 4

What is coherence?

Answer 4

constant phase relationship

Question 5

To observe interference patterns, the waves must come from?

Answer 5

coherent sources

Question 6

Constructive Interference?

Answer 6

Waves meet in phase (crest meets crests / trough meets trough).​
This results in an increase in amplitude

Question 7

Destructive Interference​?

Answer 7

Waves meet out of phase (crest meets trough)​
This results in a reduced (or zero) amplitude.​

Question 8

Interference Pattern?

Answer 8

When light from two coherent sources interferes, it produces a pattern of constructive and destructive interference.

Question 9

A bright fringe or maximum occurs when?

Answer 9

the waves meet in phase and constructive interference has taken place

Question 10

A dark fringe or minimum occurs when?

Answer 10

the waves meet out of phase and destructive interference has taken place

Question 11

Path difference in maximum?

Answer 11

whole number of wavelenght

Question 12

Path difference in minimum?

Answer 12

half number of wavelenths

Question 13

Fringe separation can be increased by?

Answer 13

increasing wavelength​

decreasing slit separation​

increasing the distance between the slits and the screen

Question 14

diffraction grating can be used to?

Answer 14

to make an interference pattern brighter and more spaced out

Question 15

Key features of the white light interference pattern (grating)​

Answer 15

The central fringe is white as for all colours of light the path difference is zero.​

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Violet light has a shorter wavelength than red light so violet light pattern is less spread out than for red light.​

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Many spectra produced, symmetrical about the central maximum.

Question 16

Key features of the white light refraction pattern​

Answer 16

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Only one spectrum produced by refraction.​

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Violet deviated the most, red the least as violet has a higher refractive index for mediums compared to red light.​

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Bright image compared to a grating spectrum that is less intense as energy is divided between several spectra.​

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Less spread out than a grating spectrum.