Q

An object is 15 cm from a mirror, and its image forms 30 cm from the mirror on the same side. What is the focal length?

RRB Group-D 13/08/2026 (12:45 PM - 2:15 PM) 2026
✓ Answer: A -10 cm
u = -15 cm and v = -30 cm. Therefore 1/f = -1/15 - 1/30 = -1/10 and f = -10 cm.
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