What is the focal length of a concave mirror if an object placed at a distance of 30 cm produces an image at a distance of 10 cm? (2021)
Practice Questions
1 question
Q1
What is the focal length of a concave mirror if an object placed at a distance of 30 cm produces an image at a distance of 10 cm? (2021)
5 cm
10 cm
15 cm
20 cm
Using the mirror formula, 1/f = 1/v + 1/u; here, v = -10 cm (real image) and u = -30 cm (object distance). Thus, 1/f = 1/(-10) + 1/(-30) = -1/6, so f = 5 cm.
Questions & Step-by-step Solutions
1 item
Q
Q: What is the focal length of a concave mirror if an object placed at a distance of 30 cm produces an image at a distance of 10 cm? (2021)
Solution: Using the mirror formula, 1/f = 1/v + 1/u; here, v = -10 cm (real image) and u = -30 cm (object distance). Thus, 1/f = 1/(-10) + 1/(-30) = -1/6, so f = 5 cm.
