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?

Explanation:

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

Here

         R₁ = 21Ω

         R₂ = 58Ω

         R₃ = 64Ω

a)      

  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

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