Exam 33: Interference and Diffraction

Light of wavelength 640 nm is incident perpendicularly from air onto a film 1000 nm thick and of 1.60 refractive index.When part of the light enters the film and is reflected back at the second face,the number of wavelengths contained along the path of this light in the film is

You coat a glass lens (n = 1.65)with MgF₂ (n = 1.38)to reduce reflection.The minimum thickness of coating required to produce destructive interference in reflected light whose wavelength in air is 560 nm is

Two side-by-side coherent light sources radiate at 600 nm.The phase difference between these two sources at a point in space is 0.582 radians.The path difference between the two sources could be

A discharge tube is known to produce two spectral lines,one at 640 nm and the other at 640.4 nm.The total number of rulings that a grating must have to just resolve these lines in the second order is

Two slits of width a = 0.020 mm are separated by a distance d = 0.05 mm and illuminated by light of wavelength $\lambda$ = 500 nm.The number of bright fringes seen in the central maximum is

If the prism spectrum of a source is a line spectrum,the grating spectrum would

You set two slits 30 mm apart and 50 cm from a screen.When you illuminate the slits with light of wavelength 600 nm,the distance between the second and third dark interference lines is

A diffraction grating has 2000 lines per centimeter and is 3.0 centimeters wide.When visible light is incident on the grating,a maximum is observed at an angle of 10º from the normal.The wavelength of the incident radiation is

You set two parallel slits 0.2 mm apart at a distance of 1 m from a screen and illuminate them with light of wavelength 600 nm.The distance between a bright spot in the interference pattern and the dark spot adjacent to it is

Suppose you observe nineteen bright fringes in the central maximum of a double-slit interference pattern.If you know that the separation of the slits d = 0.06 mm,you can conclude that the width of each slit is

Diffraction of sound waves is more readily observable than that of light waves because

Visible light from an ordinary source such as a sodium lamp can be used to produce interference effects that demonstrate the wave nature of light,provided that

A diffraction grating has 5000 lines per centimeter and is 1.5 centimeters wide.When radiation is incident upon the grating a second-order maximum is observed at an angle of 37º.The wavelength of this light is

The bending of light around an obstacle such as the edge of a slit is called

In dealing with the diffraction pattern of a single slit,we are usually interested in the location of the first minimum in light intensity because

The minimum path difference that will produce a phase difference of 180º for light of wavelength 600 nm is

You apply a material with n = 1.25 to a lens (n_g = 1.5)to make a nonreflective coating due to destructive interference at a wavelength (in a vacuum)of 555 nm.What is the minimum thickness of the coating that you need?

The yellow line of a Sodium lamp is two lines very close together at $\lambda$ ₁ = 589.592 nm and $\lambda$ ₂ = 588.995 nm.If a diffraction grating has to resolve the first order diffraction lines by an angular separation of 0.1 ^$\circ$ ,what is the least number of lines per cm for the diffraction grating?

The distance between the slits in a double-slit experiment is increased by a factor of 4.If the distance between the fringes is about the same as the distance from the slits to the screen,the distance between adjacent fringes

An antenna for receiving television signals from a satellite has a diameter of 3 m.The signals have a wavelength of 24 cm.If the diameter of the antenna is reduced to 50 cm,for what signal wavelengths does the antenna still have the same angular resolution?