Question

Three resistors, 21 Ω, 58 Ω, and 64 Ω, are connected in series, and a 0.50-A current passes through them. What are (a) the equivalent resistance and (b) the potential difference across this equivalent resistance?

Answer 1

a) Equivalent resistance is 143 Ω

b) Potential difference is 71.5 V

Explanation:

When resistors are connected in series, effective resistance is given by

                $R_{eff}=R_1+R_2+R_3+......$

Here

         R₁ = 21Ω

         R₂ = 58Ω

         R₃ = 64Ω

a)      $R_{eff}=R_1+R_2+R_3\\\\R_{eff}=21+58+64\\\\R_{eff}=143\Omega$

  Equivalent resistance is 143 Ω

b) We know

               Potential difference = Current x Resistance

               V = IR

               I = 0.5 A

               R = 143Ω

Substituting

               V = 0.5 x 143 = 71.5 V

Potential difference is 71.5 V