Question 17
Current ElectricityThree cells each of e.m.f. 1.5 V and internal resistance 2.5Ω are connected as shown in the diagram above. Find the net e.m.f. and the internal resistance.
- A.4.5V, 7.50 Ω.
- B.4.5V, 0.83 Ω.
- C.1.5V, 7.50 Ω.
- D.1.5V, 0.83 Ω.
Show the answer and explanation
Answer: D (1.5V, 0.83 Ω.)
Explanation
Identical cells in parallel give the e.m.f. of one cell, 1.5 V. Their internal resistances are in parallel: 2.5 ÷ 3 ≈ 0.83 Ω.