Question Detail
Question
A galvanometer of 50 Ω gives full scale deflection with 2 mA current. To convert it into ammeter, range of 10 A is connected with it, shunt resistance should be
Correct Answer
Option C is the correct answer.
Detailed Explanation
To convert a galvanometer into an ammeter of a desired range, a shunt resistance (Rs) is connected in parallel with the galvanometer.Given:Galvanometer resistance (Rg) = 50 ΩFull scale deflection current (Ig) = 2 mA = 0.002 ADesired ammeter range (I) = 10 AThe current flowing through the shunt resistor (Is) is I - Ig.Since the galvanometer and shunt are in parallel, the voltage across them is the same:Ig * Rg = Is * RsIg * Rg = (I - Ig) * RsRs = (Ig * Rg) / (I - Ig)Rs = (0.002 A * 50 Ω) / (10 A - 0.002 A)Rs = 0.1 / 9.998 ≈ 0.010002 ΩThis value is approximately 0.01 Ω.
Hint
Remember that for an ammeter, a shunt resistor is connected in parallel with the galvanometer. The voltage drop across the galvanometer and the shunt resistor must be equal.