Question 49
Current ElectricityA galvanometer of resistance 5.0 Ω has full-scale deflection for a current of 100 mA. How would its range be extended to 1.0 A? By placing a resistance of
- A.5/9 Ω in parallel
- B.9/5 Ω in series
- C.45 Ω in parallel
- D.45 Ω in series
- E.9/5 Ω in parallel
Show the answer and explanation
Answer: A (5/9 Ω in parallel)
Explanation
The shunt in parallel carries 0.9 A while the meter carries 0.1 A at the same p.d.: 0.9R = 0.1 × 5, so R = 5/9 Ω.