Question

A solid sphere of density η ( > 1) times lighter than water is suspended in a water tank by a string tied to its base as shown in fig. If the mass of the sphere is m then the tension in the string is given by

• A. $\left( \frac { \eta - 1 } { \eta } \right) m g$
• B. $\eta m g$
• C. $\frac { m g } { \eta - 1 }$
• D. $( \eta - 1 ) m g$

Answer 1

Answer: (D)

$( \eta - 1 ) m g$

Answer 2

Tension in spring T = upthrust – weight of sphere

$= V \eta \rho g - V \rho g$

$= ( \eta - 1 ) V \rho g$=