Chapter 34
20. A person looking into an empty container is able to see the far edge of the
container’s bottom as shown in Figure P34.20a. The height of the container is h, and
its width is d. When the container is completely filled with a fluid of index of
refraction n and viewed from the same angle, the person can see the center of a coin
at the middle of the container’s bottom as shown in Figure P34.20b. (a) Show that
the ratio h/d is given by
ℎ
𝑛2 − 1
=√
𝑑
4 − 𝑛2
(b) Assuming the container has a width of 8.00 cm and is filled with water, use the
expression above to find the height of the container. (c) For what range of values of n
will the center of the coin not be visible for any values of h and d?
Chapter 35
14. A ball is dropped at t = 0 from rest 3.00 m directly above the vertex of a concave
spherical mirror that has a radius of curvature of magnitude 1.00 m and lies in a
horizontal plane. (a) Describe the motion of the ball’s image in the mirror. (b) At what
instant or instants do the ball and its image coincide?
45. The distance between an object and its upright image is 20.0 cm. If the
magnification is 0.500, what is the focal length of the lens being used to form the
image?
Chapter 36
7. A student holds a laser that emits light of wavelength 632.8 nm. The laser beam
passes through a pair of slits separated by 0.300 mm, in a glass plate attached to the
front of the laser. The beam then falls perpendicularly on a screen, creating an
interference pattern on it. The student begins to walk directly toward the screen at
3.00 m/s. The central maximum on the screen is stationary. Find the speed of the
50th-order maxima on the screen.
45. Figure P36.35 shows a radio-wave transmitter and a receiver separated by a
distance d=50.0 m and both a distance h=35.0 m above the ground. The receiver can
receive signals both directly from the transmitter and indirectly from signals that
reflect from the ground. Assume the ground is level between the transmitter and
receiver and a 180o phase shift occurs upon reflection. Determine the longest
wavelengths that interfere (a) constructively and (b) destructively.
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