In the lesson's compound microscope model, what image does the objective supply to the eyepiece?

• A real, enlarged, inverted image
• Parallel rays straight from the object
• A virtual image already at the near point

You hold a convex lens close over a small shell, inside its focal length. What do you see?

• An upside-down, smaller image
• An upright, enlarged image
• A sharp image cast on the table

An unobstructed telescope's clear aperture diameter doubles. At the same wavelength, with diffraction-limited optics and other conditions comparable, which two gains follow?

• A wider true field and an upright final image
• A longer focal length and greater angular magnification
• More collected light and finer resolved detail

Two telescopes use converging objectives and the same 2 cm converging eyepiece, with final images at infinity. Their objective focal lengths are 40 cm and 80 cm. Which has greater angular magnification magnitude?

• Both give 20x because their eyepieces have equal focal lengths
• The 80 cm objective gives 40x; the 40 cm one gives 20x
• The 40 cm objective gives 40x; the 80 cm one gives 20x

An eyepiece has focal length 5 cm and gives a final image at infinity. Use D = 25 cm. What is its angular magnification?

A telescope's magnification increases while its eyepiece apparent field stays fixed. Why does its true field cover a smaller patch of sky?

• Increasing magnification makes the objective reject more light
• An inverted image always covers less sky than an upright image
• The fixed apparent field spans a smaller true sky angle

A microscope calculation gives a total angular magnification of -186. What does the minus sign tell you?

• The final image is inverted
• The image is 186 times smaller
• The objective is faulty

A microscope with a 10x objective and a 5x eyepiece magnifies 15x.