Physicshard · Past Paper
Two thin lenses of focal lengths 20 cm and 25 cm are placed in contact. The effective power of the combination is:
A9 D
B45 D
C5 D
D1 D
✓ Correct Answer: A — 9 D
P1 = 1/0.2 = 5D, P2 = 1/0.25 = 4D. Total P = 5 + 4 = 9D.
Share this question
More from Physics
- If a body travels with uniform acceleration, the graph of 'v^2' against 's' is a:
- What does the slope of a distance-time graph represent?
- If a sound wave travels from air into water, which property remains unchanged?
- Which of the following remains constant in uniform circular motion?
- The initial velocity of a body is u. It stops after a time t. The retardation is: