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 :

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

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 :
Answer» 80 cm 15 cm 17.7 cm 22.5 cm Solution :(a) `f_("WATER") = 4 xx f_("AIR")` air LENS is made up to glass.

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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 :

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