A lens has a focal length of 15 cm. What is the power of the lens? (2023)
Practice Questions
1 question
Q1
A lens has a focal length of 15 cm. What is the power of the lens? (2023)
+6.67 D
+7.5 D
+10 D
+15 D
Power (P) of a lens is given by P = 1/f (in meters). Here, f = 15 cm = 0.15 m, so P = 1/0.15 = +6.67 D.
Questions & Step-by-step Solutions
1 item
Q
Q: A lens has a focal length of 15 cm. What is the power of the lens? (2023)
Solution: Power (P) of a lens is given by P = 1/f (in meters). Here, f = 15 cm = 0.15 m, so P = 1/0.15 = +6.67 D.
Steps: 5
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 15 cm, we convert it to meters by dividing by 100. So, 15 cm = 15/100 = 0.15 m.
Step 3: Substitute the focal length in meters into the power formula. Now we have P = 1/0.15.
Step 4: Calculate the power. When you divide 1 by 0.15, you get approximately 6.67.
Step 5: Write the final answer. The power of the lens is +6.67 D.
