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JAMB Physics 1988 Question 41

Question 41

Current Electricity

In the circuit diagram above, the ammeter reads a current of 3 amps, when R is 5 ohms and reads 6 amps when R is 2 ohms. The value of the unknown resistance X is

Diagram for this question
  1. A.1
  2. B.2
  3. C.3
  4. D.4
Show the answer and explanation

Answer: A (1)

Explanation

E = 3(5 + X) = 6(2 + X). So 15 + 3X = 12 + 6X, giving X = 1 Ω.