Two cells, one of emf and internal resistance , the other of emf and internal resistance , are connected in parallel (like poles together) across an external resistor of . What is the current through the resistor?

Answer and explanation

Correct answer: B. 1.45 A

  1. Step 1: Let be the potential difference across the external resistor. By Kirchhoff's current law, the sum of currents delivered by the two cells equals the current through the load: .
  2. Step 2: Express currents in terms of : .
  3. Step 3: Combine like terms: .
  4. Step 4: Calculate current through the resistor: .
Answer
1.45 A.
Why not the others: results from simply taking the unweighted average emf , and erroneously treats the two cells as connected in series.

Practise more Current electricity.

Free questions with an explanation for every one, and full timed JEE Main mock tests.

All Current electricity questionsTake a mock test

More Current electricity questions