A convex lens has a focal length of 25 cm. What is the power of the lens? (2021)

A convex lens has a focal length of 25 cm. What is the power of the lens? (2021)

Step 1: Understand that the power of a lens is calculated using the formula P = 1/f, where P is the power in diopters (D) and f is the focal length in meters.
Step 2: Convert the focal length from centimeters to meters. Since the focal length is given as 25 cm, we convert it to meters by dividing by 100. So, 25 cm = 25/100 = 0.25 m.
Step 3: Substitute the focal length in meters into the power formula. Now we have P = 1/0.25.
Step 4: Calculate the power. 1 divided by 0.25 equals 4. So, P = 4 D.
Step 5: Since the lens is a convex lens, the power is positive, which means P = +4 D.

Lens Power Calculation – The power of a lens is calculated using the formula P = 1/f, where f is the focal length in meters.
Unit Conversion – Understanding the need to convert focal length from centimeters to meters for accurate calculations.