When a convex lens is placed in a medium with a refractive index closer to that of the lens than air, its focal length generally

Options

  • A. Decreases
  • B. Increases
  • C. Becomes zero
  • D. Always becomes negative
  • E. None of the above

Correct Answer (Detailed Explanation is Below)

B. Increases

Detailed Explanation

Reducing the refractive-index contrast between the lens and surrounding medium reduces its optical power, increasing its focal length.