Question

For fixed values of radii of curvature of lens, power of the lens will be ____.
Fill in the blank with the correct answer from the options given below

• A. \(P \propto (\mu - 1)\)
• B. \(P \propto \mu^2\)
• C. \(P \propto \frac{1}{\mu}\)
• D. \(P \propto \mu^{-2}\)

Answer 1

The Correct Option is A

The power (P) of a lens is given by the lensmaker's formula:

P = (μ - 1) (1/R₁ - 1/R₂)

Where:

• P is the power of the lens
• μ is the refractive index of the lens material
• R₁ and R₂ are the radii of curvature of the lens surfaces

If the radii of curvature (R₁ and R₂) are fixed, then (1/R₁ - 1/R₂) is a constant. Let's call this constant K.

So, the formula becomes:

P = (μ - 1)K

Since K is a constant, we can say that:

P ∝ (μ - 1)

Therefore, for fixed values of radii of curvature of the lens, the power of the lens is proportional to (μ - 1).

The correct answer is:

Option 1: P ∝ (μ - 1)