Question

A lens has focal length $ f = 20 \, \text{cm} $. What is the power of the lens?

• A. \( +5 \, \text{D} \)
• B. \( +10 \, \text{D} \)
• C. \( -5 \, \text{D} \)
• D. \( -10 \, \text{D} \)

Hint:

Remember: The power of a lens is the reciprocal of the focal length in meters.