Physicshard · Past Paper
What is the focal length of a magnifying glass of power 20 D?
A5 cm
B20 cm
C50 cm
D2 cm
✓ Correct Answer: A — 5 cm
f = 1/P = 1/20 = 0.05 m = 5 cm.
Share this question
More from Physics
- A car starts from rest and covers 100m in 5s. What is its acceleration?
- What is the speed of sound in a medium if a wave with a frequency of 2 kHz has a wavelength of 0.75 m?
- A solenoid of length 0.5m has 500 turns. If 2A current flows, calculate the magnetic field strength (take μ₀ = 4π x 10^-7 T m/A).
- Which of these equations is used for distance covered by a body in uniform acceleration?
- Which of these quantities can be zero for a moving body?