Question

When a spring is stretched by $10cm$, the potential energy stored is E. When the spring is stretched by $10cm$ more, the potential energy store in the spring becomes:

• A. $2E$
• B. $4E$
• C. $6E$
• D. $10E$

Answer 1

The correct option is B $4E$

For $1st$ situation,
$E=\frac{1}{2}k(10\times {10}^{-2}{)}^2$ ........ (i)

For $2nd$ situation,
$E^{\prime }=\frac{1}{2}k(20\times {10}^{-2}{)}^2$ ........ (ii)

On comparing Eqs. (i) and (ii), we get
$E^{\prime }=4E$