A copper rod of length 20 cm and cross-sectional area 2 ~mm ^2 is joined with a similar aluminium rod as shown below The resistance of pair of rods is ( _ Al =2.6 10⁻⁸ - m . and _ Cu =1.7 10⁻⁸ - m )

Step-by-step solution

The resistance of the copper rod = 1 a = 1.7 10⁻⁸ 20 10⁻² 2.0 10⁻⁶ =1.7 10⁻³ Similarly the resistance of aluminium rod =2.6 10⁻³ The equivalent resistance aligned & 1 R = 1 1.7 10⁻³ + 1 2.6 10⁻³ & R= 1.7 2.6 4.3 10⁻³=1.0 ~m aligned