JEE Main 2014 · 9 Apr · Shift 1 · Physics Q8

PhysicsSingle correct+4 / -1Question 8 of 90

In materials like aluminium and copper, the correct order of magnitude of various elastic modulii is :

Young's modulii < shear modulii < bulk modulii.

Bulk modulii < shear modulii < Young's modulii.

Shear modulii < Young's modulii < bulk modulii.

Bulk modulii < Young's modulii < shear modulii.

Answer and worked solution

Official answer: C

For Al: $G\approx26$ GPa, $Y\approx70$ GPa, $B\approx76$ GPa. For Cu: $G\approx45$ , $Y\approx120$ , $B\approx140$ GPa.

In general, for a Poisson ratio near $\frac13$ , $G=\frac{Y}{2(1+\nu)}<Y<B=\frac{Y}{3(1-2\nu)}$ . So shear < Young's < bulk.

JEE Main 2014 · 9 Apr · Shift 1, Physics question 8