Question Detail
Question
When calculating the power of a lens using the formula Power = 1/focal length, what unit must the focal length be in?
Correct Answer
Option C is the correct answer.
Detailed Explanation
The text explicitly states: 'Note that the units of focal length must be in meters when using this expression.'
Hint
Diopters are the unit for power, not focal length. Consider the standard SI unit for length.