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# A thin convex lens made from crown glass $\;\mu = \large\frac{3}{2}\;$ has focal length f .When it is measured in two different liquids having refractive indices $\;\large\frac{4}{3}\;$ and $\;\large\frac{5}{3}\;$ , it has the focal lengths $\;f_{1}\;$ and $\;f_{2}\;$ respectively .The correct relation between the focal length is :

$(a)\; f_{1} =f_{2}< f \qquad(b)\; f_{1} > f \;and \;f_{2} \;becomes\;negative\qquad(c)\;f_{2} > f \;and \;f_{1} \;becomes\;negative\qquad(d)\;f_{1}\;and\;f_{2}\;both\;become\;negative$