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A simple pendulum with a metallic bob has a time period T. IF the bob is immersed in a non viscous liquid and its time period is measured as 4 T, then the ratio of densitites of metal bob to that of the liquid will beA. `15 : 16`B. `16 : 15`C. `1 : 16`D. `16 : 1` |
Answer» Correct Answer - B `T_(2)=2pisqrt((l)/(g((rho_(m)-rho_(e))/(rho_(m)))))` `T_(2)=(T)/(sqrt(((rho_(m)-rho_(e))/(rho_(m))))) because T=2pisqrt((l)/(g))` `4T=(T)/(sqrt((rho_(m)-rho_(e))/rho_(m)))` `16=(1)/(sqrt((rho_(m)-rho_(l))/(rho_(m))))` `(rho_(m)-rho_(l))/(rho_(m))=(1)/(16)` `1-(rho_(l))/(rho_(m))=(1)/(16)` `1-(1)/(16)=(rho_(l))/(rho_(m))` `(16-1)/(16)=(rho_(l))/(rho_(m))` `(rho_(m))/(rho_(l))=(16)/(25)`. |
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