KVPY 2020-21 SA Exam Previous Papers

Question : 17 of 80

Marks: +1, -0

Consider two wires of same material having their ratio of radii to be 2 : 1. If these two wires are stretched by equal force, the ratio of stress produced in them is

$1/4$
$1/2$
$3/4$
1

Validate

Solution:

Given ratio of radii

{r_{1}}/{r_{2}}={2}/{1}

(Material is same)Stress

=\σ={F}/{A}

{\σ_{1}}/{\σ_{2}}={F_{1}}/{A_{1}} {A_{2}}/{F_{2}}={F_{1}}/{F_{2}} {A_{2}}/{A_{1}}

={A_{2}}/{A_{1}}={\πr_{2}^{2}}/{\πr_{1}^{2}}\;\;\;\;\; \{\∵ f_{1}=f_{2}\}

=({r_{2}}/{r_{1}})^{2}={1}/{4}

Go to Question:

Prev Question

Next Question