2026 · Q16
An object is placed at a distance of 15 cm in front of a concave mirror with a radius of curvature of 20 cm. Which one among the following statements is correct for the image formed?
General KnowledgePhysics
- AThe image is 30 cm from the mirror on the same side as the object.
- BThe image is formed at a distance of 30 cm behind the mirror.
- CThe image is 60 cm from the mirror on the same side as the object.
- DThe image is formed at a distance of 60 cm behind the mirror.
Explanation
For the concave mirror, focal length f = R/2 = 10 cm, and the object distance u = 15 cm. From the mirror formula 1/f = 1/v + 1/u: 1/10 = 1/v + 1/15, so 1/v = 1/10 - 1/15 = 1/30, giving v = 30 cm. The positive image distance means a real image formed 30 cm in front of the mirror, on the same side as the object. Images behind the mirror would be virtual, which does not occur for this object position.