If the wavelength of light is doubled, by what fraction does the amount of the light scattered by Earth's atmosphere change? Is the amount of light scattered at the new wavelength larger or smaller than the amount of light scattered at the old wavelength?

Indicate whether each of the following is a real image or a virtual image. (a) Image on the retina in a person's eye (b) Image one sees in a rearview mirror (c) Image one sees on a movie screen (d) Image one sees through a magnifying lens

Would the critical angle for a glass-water interface be less than, equal to, or greater than the critical angle for a glassair interfacer Explain your choice.

After hitting a ball into a water trap, a golfer looks into the pond and spies the ball within apparent easy reach. Reaching in to retrieve the ball, the golfer is surprised to find that it cannot be grasped even with a fully extended arm. Explain why the golfer was deceived into thinking that the location of the ball was close at hand.

Describe how you could use two large, circular Polaroid filters in front of a circular window as a kind of window shade.

An interference pattern is formed by sending red light through a pair of narrow slits. If blue light is then used, the spacing of the bright areas (where constructive interference takes place) won't be the same. How will it be different? Why?

Consider Figure mentioned below. At which of the lettered positions would an observer be able to see the image of the dot in the mirror?

Light traveling along direction $\mathrm{SO}$ strikes the surface of a plane mirror. Which of the paths $O P, O Q, O R$, or $U I$ best describes the path of the light reflected from the mirror? Defend your choice by appealing to the appropriate law(s) of optics.

Compute the approximate ratio of the amount of blue light in scattered sky light to the amount of orange.

If the mirror described in the previous problem is used to form an image of the same object now located $16 \mathrm{~cm}$ in front of the mirror, what would the new image position be? Assuming that the magnification equations developed for lenses also apply to mirrors, describe the image thus formed.

(II) A thin oil slick $\left(n_0=1.50\right)$ floats on water $\left(n_{\mathrm{w}}=1.33\right)$. When a beam of white light strikes this film at normal incidence from air, the only enhanced reflected colors are red $(650 \mathrm{~nm})$ and violet $(390 \mathrm{~nm})$. From this information, deduce the (minimum) thickness $t$ of the oil slick.

An observer $O$ stands in front of a plane mirror. Which of the numbered locations 1 through 5 best represents the location of the image of the source $S$ seen by the observer? Justify your choice by appealing to the anoropriate law (s) of optics.

The unit of electric charge, the coulomb, is the charge on

Compared to a person's height, what is the minimum length (top to bottom) of a mirror that will allow the person to see a complete image of themselves from head to toe?