Concepts Of Physics MCQ Edition [Volume 1]
- Exam
- Concepts Of Physics MCQ Edition [Volume 1]
- Subject
- Physics
- Chapter
- Geometrical Optics
Concepts Of Physics MCQ Edition [Volume 1] · Physics · Geometrical Optics
Consider a double convex lens that has two surfaces of equal radii...
Consider a double convex lens that has two surfaces of equal radii and a refractive index . The focal length is given by:
Options
- A
- B
- C
- D
Correct answer
C.
Step-by-step solution
Using the lens maker's formula:
\dfrac{1}{f} = (m - 1) \left(\dfrac{1}{R_1} - \dfrac{1}{R_2} \right)
For a double convex lens, the radii of curvature are and .
Given :
\dfrac{1}{f} = (
\dfrac{1}{f} = 0.5 \left(\dfrac{2}{R} \right)
\dfrac{1}{f} = \dfrac{1}{R}
\dfrac{1}{f} = (m - 1) \left(\dfrac{1}{R_1} - \dfrac{1}{R_2} \right)
For a double convex lens, the radii of curvature are and .
Given :
\dfrac{1}{f} = (
\dfrac{1}{f} = 0.5 \left(\dfrac{2}{R} \right)
\dfrac{1}{f} = \dfrac{1}{R}