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.)

A pair of slits, separated by 0.150 mm, is illuminated by light having a wavelength of $\lambda = 643$ nm. An interference pattern is observed on a screen 140 cm from the slits. Consider a point on the screen located at y = 1.80 cm from the central maximum of this pattern. Express this path difference in terms of the wavelength.

A pair of slits, separated by 0.150 mm, is illuminated by light having a wavelength of $\lambda = 643$ nm. An interference pattern is observed on a screen 140 cm from the slits. Consider a point on the screen located at y = 1.80 cm from the central maximum of this pattern. What is the path difference $\delta$ for the two slits at the location y?

Fingerprints left on a piece of glass such as a windowpane can show colored spectra like that from a diffraction grating. Why?

Your automobile has two headlights. What sort of interference pattern do you expect to see from them? Why?

A laser beam $(\lambda=632.8 \mathrm{~nm})$ is incident on two slits $0.200 \mathrm{~mm}$ apart. How far apart are the bright interference fringes on a screen $5.00 \mathrm{~m}$ away from the double slits?

A pair of slits, separated by 0.150 mm, is illuminated by light having a wavelength of $\lambda = 643$ nm. An interference pattern is observed on a screen 140 cm from the slits. Consider a point on the screen located at y = 1.80 cm from the central maximum of this pattern. Will the interference correspond to a maximum, a minimum, or an intermediate condition?

A pair of slits, separated by 0.150 mm, is illuminated by light having a wavelength of $\lambda = 643$ nm. An interference pattern is observed on a screen 140 cm from the slits. Consider a point on the screen located at y = 1.80 cm from the central maximum of this pattern. Express this path difference in terms of the wavelength.

A pair of slits, separated by 0.150 mm, is illuminated by light having a wavelength of $\lambda = 643$ nm. An interference pattern is observed on a screen 140 cm from the slits. Consider a point on the screen located at y = 1.80 cm from the central maximum of this pattern. What is the path difference $\delta$ for the two slits at the location y?

Fingerprints left on a piece of glass such as a windowpane can show colored spectra like that from a diffraction grating. Why?

A laser beam $(\lambda=632.8 \mathrm{~nm})$ is incident on two slits $0.200 \mathrm{~mm}$ apart. How far apart are the bright interference fringes on a screen $5.00 \mathrm{~m}$ away from the double slits?

Your automobile has two headlights. What sort of interference pattern do you expect to see from them? Why?

Two sinusoidal waves are moving through a medium in the same direction, both having amplitudes of $3.00 \mathrm{~cm}$, a wavelength of $5.20 \mathrm{~m}$, and a period of $6.52 \mathrm{~s}$, but one has a phase shift of an angle $\phi$. What is the phase shift if the resultant wave has an amplitude of $5.00 \mathrm{~cm}$ ? [Hint: Use the trig identity $\sin u+\sin v=2 \sin \left(\frac{u+v}{2}\right) \cos \left(\frac{u-v}{2}\right)$

Sound waves travel horizontally from a source to a receiver. Assume that the source has a speed u, that the receiver has a speed v (in the same direction) and that a wind of speed w is blowing from the source toward the receiver. Show that, if the source emits sound of frequency $\nu_{0}$, and if the speed of sound in still air is V, the frequency recorded by the receiver is given by $\nu=\nu_{0} \frac{V-v+w}{V-u+w}$ Note that if the velocities of source and receiver are equal, the existence of the wind makes no difference to the observed frequency of the received signal.