Question Detail
Question
A concave mirror of radius curvature 20 cm has an object placed 20 cm from it. Determine the distance of the image formed from the mirror.
Correct Answer
Option B is the correct answer.
Detailed Explanation
The focal length (f) of a concave mirror is half its radius of curvature: f = R/2 = 10 cm. Using the mirror equation: 1/f = 1/u + 1/v. Given u = -20 cm (object distance is negative in sign convention). Solving: 1/10 = 1/(-20) + 1/v => 1/v = 1/10 + 1/20 = 3/20 => v = 20/3 ≈ 6.67 cm. However, the sign convention might be different. If the object is at the center of curvature (20 cm), the image is formed at the same point, so v = 20 cm.
Hint
Use the mirror equation: 1/f = 1/u + 1/v. Remember that the focal length (f) is half the radius of curvature. For a concave mirror, if the object is at the center of curvature, the image is formed there as well.