AP EAMCET20225 Jul 2022Evening ShiftPhysicsMechanical Properties of SolidsActual
A copper wire of length 2.4 ~m and an aluminum wire of length 0.7 ~m , both having diameter 2 ~mm , are connected end to end. When stretched by a load, the obtained elongation is found to be 0.6 ~mm .The applied load is (Young's modulus of copper =1.2 10¹¹ Nm ⁻² and Young's modulus of aluminum =0.7 10¹¹ Nm ⁻² )
Options
- A12 N
- B24 N
- C20 N
- D80 N
Correct answer
C. 20 N
Step-by-step solution
l= F l₁ y ₁ ~A + F l₂ y ₂ ~A 0.6 10⁻³= F (10⁻³ )^2 [ 2.4 1.2 10¹¹ + 0.7 0.7 10¹¹ ] aligned & 0.6 10⁻⁹= F [2 10⁻¹¹+10⁻¹¹ ] & 0.6 10⁻⁹= F 3 10⁻¹¹ & F = 0.6 10⁻⁹ 3 10⁻¹¹ =20 N aligned