Exam 36: Diffraction

The diagram shows a single slit with the direction to a point P on a distant screen (not shown).At P, the pattern has its maximum nearest the central maximum.If X and Y are the edges of the slit, what is the path length difference (PX)- (PY)?

A beam of x rays of wavelength 0.10 nm is found to diffract in second order from the face of a LiF crystal at a Bragg angle of 30 ° .The distance between adjacent crystal planes is about:

Light of wavelength 480 nm falls on a slit of width 3.5 µm.What is the relative intensity (that is, the value of I/I_m)of the diffraction pattern at an angle of 18°?

A beam of white light (from 400 nm for violet to 700 nm for red)is normally incident on a diffraction grating.It produces two orders on a distant screen.Which diagram below (R = red, V = violet)correctly shows the pattern on the screen?

Light of wavelength 550 nm is incident on a diffraction grating that is 1 cm wide and has 1000 slits.What is the dispersion of the m = 2 line?

A beam of x-rays of wavelength 0.20 nm is diffracted by a set of planes in a crystal whose separation is 3.1*10^-8 cm.The smallest angle between the beam and the crystal planes for which a reflection occurs is:

A point source of monochromatic light is placed in front of a soccer ball and a screen is placed behind the ball.The light intensity pattern on the screen is best described as:

In the equation d sin $\theta$ = m $\lambda$ for the lines of a diffraction grating, m is:

A light beam incident on a diffraction grating consists of waves with two different wavelengths.The separation of the two first order lines is great if:

The resolving power of a diffraction grating is defined by R = $\lambda$ / $\Delta$ $\lambda$ .Here $\lambda$ and $\lambda$ + $\Delta$$\lambda$ are:

When the atmosphere is not quite clear, one may sometimes see colored circles concentric with the Sun or the Moon.These are generally not more than a few diameters of the Sun or Moon and invariably the innermost ring is blue.The explanation for these phenomena involves:

To obtain greater dispersion by a diffraction grating:

If white light is incident on a diffraction grating:

Two wavelengths, 800 nm and 600 nm, are used separately in single-slit diffraction experiments.The diagram shows the intensities on a far-away viewing screen as function of the angle made by the rays with the straight-ahead direction.If both wavelengths are then used simultaneously, which point corresponds to the smallest angle at which the light on the screen is purely 800-nm light?

Consider a single-slit diffraction pattern caused by a slit of width a.There is a minimum at sin(\theta\)equal to:

Light of wavelength $\lambda$ is normally incident on some plane optical device.The intensity pattern shown is observed on a distant screen ( $\theta$ is the angle measured to the normal of the device).The device could be:

At the first minimum adjacent to the central maximum of a single-slit diffraction pattern the phase difference between the Huygens wavelet from the top of the slit and the wavelet from the midpoint of the slit is:

A plane wave with a wavelength of 500 nm is incident normally on a single slit with a width of 5.0 *10^-6 m.Consider waves that reach a point on a far-away screen such that rays from the slit make an angle of 1.0°with the normal.The difference in phase for waves from the top and bottom of the slit is:

The dispersion of a diffraction grating indicates:

A diffraction grating just resolves the wavelengths 400.0 nm and 400.1 nm in first order.The number of slits in the grating is: