A hollow double concave lens is made of very thin transparent material. It can be filled with air or either of two liquids or having refractive indices and respectively . The lens will diverge a parallel beam of light if it is filled with

Question

A hollow double concave lens is made of very thin transparent material. It can be filled with air or either of two liquids $L_{1}$ or $L_{2}$ having refractive indices $μ_{1}$ and $μ_{2}$ respectively $(μ_{2} > μ_{1} > 1)$ . The lens will diverge a parallel beam of light if it is filled with [2000]

Smart Achievers · Accepted Answer

(4)

The lens maker formula,

$\frac{1}{f} = (\frac{μ_{2}}{μ_{1}} - 1) (\frac{1}{R_{1}} - \frac{1}{R_{2}})$

If $μ_{2} > μ_{1}$ , the concave lens maintains its nature; otherwise, the nature of the lens will be reversed.

So, the lens should be filled with $L_{2}$ and immersed in $L_{1}$ .

Solution

1 air and placed in air

2 air and immersed in $L_{1}$

3 $L_{1}$ and immersed in $L_{2}$

4 $L_{2}$ and immersed in $L_{1}$

Ans.
(4)

The lens maker formula,

$\frac{1}{f} = (\frac{μ_{2}}{μ_{1}} - 1) (\frac{1}{R_{1}} - \frac{1}{R_{2}})$

If $μ_{2} > μ_{1}$ , the concave lens maintains its nature; otherwise, the nature of the lens will be reversed.

So, the lens should be filled with $L_{2}$ and immersed in $L_{1}$ .

Want Us to Email you About Special Offers & Updates?

Solution

Q. A hollow double concave lens is made of very thin transparent material. It can be filled with air or either of two liquids L1 or L2 having refractive indices μ1 and μ2 respectively (μ2>μ1>1). The lens will diverge a parallel beam of light if it is filled with [2000]

1 air and placed in air

2 air and immersed in L1

3 L1 and immersed in L2

4 L2 and immersed in L1

Ans. (4) The lens maker formula, 1f=(μ2μ1-1)(1R1-1R2) If μ2>μ1, the concave lens maintains its nature; otherwise, the nature of the lens will be reversed. So, the lens should be filled with L2 and immersed in L1.

Want Us to Email you About Special Offers & Updates?

2 air and immersed in $L_{1}$

3 $L_{1}$ and immersed in $L_{2}$

4 $L_{2}$ and immersed in $L_{1}$

Ans.
(4)

The lens maker formula,

$\frac{1}{f} = (\frac{μ_{2}}{μ_{1}} - 1) (\frac{1}{R_{1}} - \frac{1}{R_{2}})$

If $μ_{2} > μ_{1}$ , the concave lens maintains its nature; otherwise, the nature of the lens will be reversed.

So, the lens should be filled with $L_{2}$ and immersed in $L_{1}$ .