Q120 / 150 · MHT CET 2022 (10 Aug Shift 1) · Physics

When a long spring of $4 \mathrm{~cm}$ is stretched by $1 \mathrm{~cm}$, the potential energy stored in the spring is $U$. If it is stretched by $4 \mathrm{~cm}$, the potential energy stored in it is

  • A
    $4 U$
  • Correct answer
    B
    $16 U$
  • C
    $9 U$
  • D
    $25 U$

Solution

The potential energy $U$ relates to an extension $x$ via, $\begin{aligned} & U=\frac{1}{2} K x^2 \\ & \therefore \frac{U^{\prime}}{U}=\frac{x^{\prime 2}}{x^2}=\frac{4^2}{1^2}=16\end{aligned}$

Hence, the correct answer is option: 'B'.

Relevant Questions