Geometrical OpticsEasy
Question
A hollow doubled concave lense is made of very thin transparaent material. It can be filled with air or either of two liquids L1 or L2 having refracting indices n1 and n2 respectively (n2 > n1 > 1). The lens will divege a parallel beam of light if it is filled with
Options
A.air and placed in air
B.air and immersed in L1
C.L1 and immersed in L2
D.L2 and immersed in L1
Solution
The lens maker′s formula is
Where, nL = Refractive index of lens and
nL = Refractive index of medium
In case of double concave lens, R1 is negative and R1 is positive. Therefore,
will be negative.
For the lens to be diverging in nature, focal length f should be negative of
should be positve or nL > nm but since n2 > n1 (given), therefore the lens should be filled with L2 and immersed L1.
Where, nL = Refractive index of lens and
nL = Refractive index of medium
In case of double concave lens, R1 is negative and R1 is positive. Therefore,
will be negative. For the lens to be diverging in nature, focal length f should be negative of
should be positve or nL > nm but since n2 > n1 (given), therefore the lens should be filled with L2 and immersed L1.Create a free account to view solution
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