What is the focal length of a 10D lens?

To determine the focal length of a lens based on its power in diopters (D), the formula to use is:

[ \text{Focal Length (meters)} = \frac{1}{\text{Power (diopters)}} ]

In this case, the lens has a power of 10 diopters. Applying the formula:

[ \text{Focal Length} = \frac{1}{10} = 0.1 \text{ meters} ]

Since 0.1 meters is equivalent to 10 centimeters, this confirms that the focal length is indeed 10 centimeters. This understanding is key in optics where the relationship between the power of a lens and its focal length is fundamental.

In the context of the choices, recognizing that 10 centimeters corresponds directly to the calculation based on the given diopter value solidifies the answer. The other values do not align with the calculations derived from the lens's power, leading to a clear selection of 10 centimeters as the correct focal length.