Answer: 60 cm.
- A 12 cm
- B 20 cm
- C 30 cm
- D 60 cm
Correct answer: D. 60 cm
Explanation: 1/v − 1/u = 1/f with u = −30: 1/v = 1/20 − 1/30 = 1/60, so v = 60 cm.
Concave mirror ray construction: a ray parallel to the axis reflects through F, and a ray through F reflects parallel, locating the inverted real image. Image: Maxmath12, CC0, via Wikimedia Commons.
Concept context
Reflection, refraction, lenses, mirrors, total internal reflection.