Equal potentials are applied on an iron and copper wire of same length. In order to have the same current flow in the two wires, the ratio r (iron)/r (copper) of their radii must be (Given that specific resistance of iron = \[1.0\times {{10}^{-7}}\]ohm?m and specific resistance of copper = \[1.7\times {{10}^{-8}}\]ohm-m) [MP PMT 2000]

• A.            About 1.2
• B.                                      About 2.4
• C.            About 3.6                              
• D.            About 4.8