Chapter 26 Review Questions

You will observe a total eclipse of the sun when

(a) you stand in the penumbra of the moon's shadow

(b) you stand in the umbra of the moon's shadow

(c) sunlight diffracts around the moon

(d) sunlight reflects from the moon to the earth

Which of the following will cast a shadow that has an umbra but no penumbra?

(a) the sun

(b) an incandescent lamp

(c) a fluorescent lamp

(d) a point source of light

The speed of light

(a) has never been measured

(b) is about the same as that of sound

(c) is infinitely fast

(d) is very fast, but not infinite

What is the purpose of the pupil in an eye?

(a) to adjust the focal length of the lens

(b) to adjust the amount of light passing through the lens

(c) to focus the image

(d) to change the width of the field of view