Chapter 24

Question 1

What are the conditions for interference?

Answer 1

Light produced by ordinary light sources is incoherent and can be made coherent by placing a slit in front of the source to illuminate two other slits
Can also use laser as light source (laser light is of a single wavelength)

Question 2

What is double slit interference?

Answer 2

Light from two slits produces a pattern on a screen placed across from slits
Alternating brightness and darkness

Slide 17-19 Feb 26
Slide 24, 26

Question 3

How is destructive and constructive interference undergone by double slit waves?

Answer 3

Destructive- when the oath lengths differ by half a wavelength they are 180 degrees out of sync
Slide 22 feb 26
Constructive- when the oath lengths differ by a wavelength, the waves are in phase
Slide 23

Question 4

What is diffraction?

Answer 4

As the opening or object size decreases, structure (maxima and minima) appear in the diffraction pattern due to interference of the waves coming from different points

Narrower opening, broader the diffraction (more spread out)
Wider the opening, closer the diffraction

Slide 6 Feb 28

Question 5

What is single slit diffraction?

Answer 5

Light from one portion of the slit interferes with light from any other portion

Destructive interference (dark) and constructive (bright)
Slide 8 Feb 28

Sinθ=λ/a

Slide 13-14 Feb 28

Question 6

What is the range of visible wavelengths?

Answer 6

400nm (violet) - 700nm (red)

Question 7

What is the diffraction grating?

How are the bright fringes affects by the number of slits?

Answer 7

Diffraction grating consists of large number of parallel, narrow, equally spaced slits
Spacing is specified in terms of # of slits per unit distance
d= slit separation = 1/(slits per distance)

As the number of slits through which light passes is increased, the bright fringes become narrower (sharper) and brighter

Position of fringes do not change as long as slot spacing doesn’t change

Maxima occurs as dsinθ=mλ

Slide 18 Feb 28

Question 8

How do gratings split light into its spectral components?

Answer 8

Since the locations of the maxima are wavelength dependant, the grating separates light from a multi wavelength source into its spectral components