A double convex lens of focal length 20 cm is made of glass of refract – McqOptions

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1.	A double convex lens of focal length 20 cm is made of glass of refractive index 3 / 2. When placed completely in water \[{{(}_{a}}{{\mu }_{w}}=4/3)\], its focal length will be [CBSE PMT 1990; MP PMT/PET 1998]
A.	80 cm
B.	15 cm
C.	17.7 cm
D.	22.5 cm
Answer» B. 15 cm

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