If a lens of focal lenth 20 cm, made of glass of refractive index 1.5, is placed in a liquid of refractiven index 1.25, the focal length of the lens becomes _______.

If a lens of focal lenth 20 cm, made of glass of refractive index 1.5,

1.	If a lens of focal lenth 20 cm, made of glass of refractive index 1.5, is placed in a liquid of refractiven index 1.25, the focal length of the lens becomes _______.
Answer» Solution :Hint : `SIN i_(c)=(n_(w))/(n_(g))=((4)/(3))/((5)/(3))=(4)/(5)`

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If a lens of focal lenth 20 cm, made of glass of refractive index 1.5, is placed in a liquid of refractiven index 1.25, the focal length of the lens becomes _______.

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