What is the power of a lens that has a focal length of 2 meters?

What is the power of a lens that has a focal length of 2 meters?

• A. 1.0 D
• B. 0.50 D
• C. 2.0 D
• D. 0.25 D

Answer: (B)

The power of a lens is calculated using the formula: \[ \text{Power (D)} = \frac{1}{\text{Focal Length (meters)}} \] In this case, the focal length given is 2 meters. Therefore, the calculation for power would be: \[ \text{Power} = \frac{1}{2} = 0.5 \, \text{D} \] This indicates that the lens has a power of 0.5 diopters, which aligns with the focal length of 2 meters. The power of a lens is inversely related to its focal length; as the focal length increases, the power decreases. This negative correlation is crucial in understanding how lens strength is defined. To clarify the context, a power of 0.5 D indicates that the lens diverges light at a slower rate compared to a lens with a higher power, making it suitable for certain optical applications. Understanding this relationship is fundamental for anyone studying lenses and their properties in the field of optics.

The power of a lens is calculated using the formula:

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

In this case, the focal length given is 2 meters. Therefore, the calculation for power would be:

[ \text{Power} = \frac{1}{2} = 0.5 , \text{D} ]

This indicates that the lens has a power of 0.5 diopters, which aligns with the focal length of 2 meters. The power of a lens is inversely related to its focal length; as the focal length increases, the power decreases. This negative correlation is crucial in understanding how lens strength is defined.

To clarify the context, a power of 0.5 D indicates that the lens diverges light at a slower rate compared to a lens with a higher power, making it suitable for certain optical applications. Understanding this relationship is fundamental for anyone studying lenses and their properties in the field of optics.