When you receive a chest $x$-ray at a hospital, the $x$-rays pass through a series of parallel ribs in your chest. Do the ribs act as a diffraction grating for $\mathrm{x}$-rays?

A simple way of observing an interference pattern is to look at a distant light source through a stretched handkerchief or an open umbrella. Explain how this works.

A thin film of glass ( $n=1.50$ ) floats on a liquid of $n=1.35$ and is illuminated by light of $\lambda=580 \mathrm{~nm}$ incident from air above it. Find the minimum thickness of the glass, other than zero, that will produce destructive interference in the reflected light.

Why is it so much easier to perform interference experiments with a laser than with an ordinary light source?

A standard sheet of paper (first paper) measures $81 / 2$ by $11$ inches. A second sheet of paper is half as long and half as wide as the one described as the first paper. By what factor is its area less than the area found with first paper?

Estimate the rate that your hair grows in meters per second. Indicate any assumptions you made.

Suppose the film has an index of refraction of $1.36$ and is surrounded by air on both sides. Find the minimum thikkness that will produce constructive interference in the reflected light when the film is illuminated by light of wavelength $500 \mathrm{~nm}$.

Determine the minimum thickness of a soap film ( $n=$ 1.330) that will result in constructive interference of (b) the blue $\mathrm{H}_\gamma$ line $(\lambda=434.0 \mathrm{~nm})$

Certain sunglasses use a polarizing material to reduce the intensity of light reflected from shiny surfaces, such as water or the hood of a car. What orientation of the transmission axis should the material have to be most effective?

Determine the minimum thickness of a soap film ( $n=$ 1.330) that will result in constructive interference of (a) the red $\mathrm{H}_\alpha$ line ( $\lambda=656.3 \mathrm{~nm}$ );

Would it be possible to place a nonreflective coating on an airplane to cancel radar waves of wavelength 3 cm?

Suppose reflected white light is used to observe a thin, transparent coating on glass as the coating material is gradually deposited by evaporation in a vacuum. Describe some color changes that might occur during the process of building up the thickness of the coating.

The waves from a radio station can reach a home receiver by two different paths. One is a straight-line path from the transmitter to the home, a distance of $30.0 \mathrm{~km}$. The second path is by reflection from a storm cloud. Assume that this reflection takes place at a point midway between receiver and transmitter. If the wavelength broadcast by the radio station is $400 \mathrm{~m}$, find the minimum height of the storm cloud that will produce destructive interference between the direct and reflected beams. (Assume no phase changes on reflection.)

In everyday experience, why are radio waves polarized, whereas light is not?