Two wires $A$ and $B$ are stretched by the same load. The radius of wire $A$ is double the radius of wire…

Two wires $A$ and $B$ are stretched by the same load. The radius of wire $A$ is double the radius of wire $\mathrm{B}$. The stress on the wire $\mathrm{B}$ as compared to the stress on the wire A is
  1. twice
  2. four times
  3. half
  4. equal

Solution

stress $=\frac{\text { Force }}{\text { Area }}$ $\therefore$ stress $\propto \frac{1}{\pi r^{2}}$ Thus, $\frac{S_{B}}{S_{A}}=\left[\frac{r_{A}}{r_{B}}\right]^{2}=(2)^{2} \Rightarrow S_{B}=4 S_{A}$

Asked in: MHT CET 2020 (16 Oct Shift 2)

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