Commons

ProblemsKey√∫⋆A computerized answer check is available online.A problem that requires calculus.A difficult problem.1 The natives of planet Wumpus play pool using light rays onan eleven-sided table with mirrors for bumpers, shown in the figureon the next page. Trace this shot accurately with a ruler to revealthe hidden message. To get good enough accuracy, you’ll need tophotocopy the page (or download the book and print the page) anddraw in the normal at each place where the ray strikes a bumper.Problem 1.Problem 3.2 The figure on the next page shows a curved (parabolic) mirror,with three parallel light rays coming toward it. One ray is approachingalong the mirror’s center line. (a) Trace the drawing accurately,and continue the light rays until they are about to undergo theirsecond reflection. To get good enough accuracy, you’ll need to photocopythe page (or download the book and print the page) anddraw in the normal at each place where a ray is reflected. Whatdo you notice? (b) Make up an example of a practical use for thisdevice. (c) How could you use this mirror with a small lightbulb toproduce a parallel beam of light rays going off to the right?3 The figure shows four points where rays cross. Of these, whichare image points? Explain.158 Chapter 7 The Ray Model of Light