A bimetallic cylindrical bar of cross sectional area 1 m2 is made by bonding Steel

Q. A bimetallic cylindrical bar of cross sectional area 1 m² is made by bonding Steel (Young’s modulus = 210 GPa) and Aluminium (Young’s modulus = 70 GPa) as shown in the figure. To maintain tensile axial strain of magnitude 10^-6 in Steel bar and compressive axial strain of magnitude 10^-6 in Aluminum bar, the magnitude of the required force P (in kN) along the indicated direction is

(A) 70                         (B) 140                       (C) 210                      (D) 280

Ans: 280