Assertion $A$: A bar tapers from a diameter of $d_1$ to a diameter of $d_2$ over its length $\text{'}l\text{'}$ and is subjected to a tensile

force $\text{'}p\text{'}$. If extension is calculated based on treating it as a bar of average diameter, the calculated extension will be

more than the actual extension. 

Reason 

• • 1

    Both $A$ and $R$ are true and $R$ is the correct explanation of $A$

  • 2

    Both $A$ and $R$ are true but $R$ is not a correct explanation of $A$

  • 3

    $A$ is true but $R$ is false 

  • 4

    $A$ is false but $R$ is true