A lens has a power of +2.0 D. What is its focal length?
Practice Questions
Q1
A lens has a power of +2.0 D. What is its focal length?
50 cm
25 cm
20 cm
10 cm
Questions & Step-by-Step Solutions
A lens has a power of +2.0 D. What is its focal length?
Step 1: Understand that the power of a lens (P) is related to its focal length (f) by the formula P = 1/f.
Step 2: Identify the power of the lens given in the question, which is +2.0 D.
Step 3: Use the formula to find the focal length: f = 1/P.
Step 4: Substitute the power into the formula: f = 1/2.0.
Step 5: Calculate the focal length: f = 0.5 meters.
Step 6: Convert the focal length from meters to centimeters: 0.5 m = 50 cm.
Lens Power and Focal Length – The power of a lens is the reciprocal of its focal length, measured in diopters (D). A positive power indicates a converging lens.
