A production-line inspector wants a mirror that produces an image that is upright with a magnification of 7.5 when it is located 14.0 mm from a machine part. a. What kind of mirror would do this job? b. What is its radius of curvature?

A public school law requires a minimum illuminance of 160 lx at the surface of each student’s desk. An architect’s specifications call for classroom lights to be located 2.0 m above the desks. What is the minimum luminous flux that the lights must produce?

The power output of a cyclist moving at a constant speed of 6.0 m/s on a level road is 120 W. (a) What is the force exerted on the cyclist and the bicycle by the air? (b) By bending low over the handlebars, the cyclist reduces the air resistance to 18 N. If she maintains a power output of 120 W, what will her speed be?

Look carefully at an ordinary, frosted, incandescent bulb. Is it a luminous or an illuminated source?

A magician uses a concave mirror with a focal length of 8.0 m to make a 3.0-m-tall hidden object, located 18.0 m from the mirror, appear as a real image that is seen by his audience. Draw a scale ray diagram to find the height and location of the image.

A 50-cm-tall dog stands 3 m from a plane mirror and looks at its image. What is the image position, height, and type?

A certain kind of glass has an index of refraction of 1.650 for blue light of wavelength 430 nm and an index of 1.615 for red light of wavelength 680 nm. If a beam containing these two colors is incident at an angle of $30.00 ^ { \circ }$ on a piece of this glass, what is the angle between the two beams inside the glass?

Entropy can be used as a measure of the overall health of an ecosystem—higher entropy correlates with better health. A thermal image of a landscape, where color indicates temperature, can be used for a quick assessment. What would be the thermal signature of a healthy ecosystem?

A convenience store uses a surveillance mirror to monitor the store’s aisles. Each mirror has a radius of curvature of 3.8 m. a. What is the image position of a customer who stands 6.5 m in front of the mirror? b. What is the image height of a customer who is 1.7 m tall?

The reflecting surfaces of two intersecting flat mirrors are at an angle $\theta\left(0^{\circ}<\theta<90^{\circ}\right)$. For a light ray that strikes the horizontal mirror, show that the emerging ray will intersect the incident ray at an angle $\beta=180^{\circ}-2 \theta$

A baseball fan on a warm summer day $\left(30^{\circ} \mathrm{C}\right)$ sits in the bleachers 152 m away from home plate. a. What is the speed of sound in air at $30^{\circ} \mathrm{C}$? b. How long after seeing the ball hit the bat does the fan hear the crack of the bat?

You are floating just offshore at the beach. Even though the waves are steadily moving in toward the beach, you don’t move any closer to the beach. a. What type of wave are you experiencing as you float in the water? b. Explain why the energy in the wave does not move you closer to shore. c. In the course of 15 s you count ten waves that pass you. What is the period of the waves? d. What is the frequency of the waves? e. You estimate that the wave crests are 3 m apart. What is the velocity of the waves? f. After returning to the beach, you learn that the waves are moving at 1.8 m/s. What is the actual wavelength of the waves?

Is the cross product associative? If so, prove it; if not, provide a counterexample (the simpler the better).

$$(\vec{A}\times\vec{B})\times\vec{C}\overset{?}{=}\vec{A}\times(\vec{B}\times\vec{C})$$

A ball is positioned 22 cm in front of a spherical mirror and forms a virtual image. If the spherical mirror is replaced with a plane mirror, the image appears 12 cm closer to the mirror. What kind of spherical mirror was used?