Question 20
Current ElectricityA milliameter with full scale deflection of 10 mA has an internal resistance of 5 ohms. It would be converted to an ammeter with a full scale deflection of 1 A by connecting a resistance of
- A.5/99 ohm in series with it
- B.5/99 ohm in parallel with it
- C.99/5 ohm in parallel with it
- D.99/5 ohm in series with it
- E.2 ohms in series with it.
Show the answer and explanation
Answer: B (5/99 ohm in parallel with it)
Explanation
A shunt goes in parallel and carries 1 − 0.01 = 0.99 A while the meter carries 0.01 A at the same p.d.: 0.99R = 0.01 × 5, so R = 5/99 Ω.