Question

A copper sphere attached to the bottom of a vertical spring is oscillating with time period $10\text{s}$. If the copper sphere is immersed in a fluid (assume the viscosity of the fluid is negligible) of specific gravity $\frac{1}{4}$ of that of the copper, then time period of the oscillation is

• A. $5\text{s}$
• B. $10\text{s}$
• C. $2.5\text{s}$
• D. $20\text{s}$

Answer 1

The correct option is B $10\text{s}$

Given, Time period of sphere and spring system $\left(T\right)=10\text{s}$.
Since, the viscosity of liquid is negligible, there is no change in $m$ and $K$.
$\therefore$ Time period remains constant.
Hence, option (b) is correct.