Q. A galvanometer having a coil resistance of 60 Ω shows full scale deflection when a current of 1.0 amp passes through it. It can be converted into an ammeter to read currents upto 5.0 amp by:
A) putting in series a resistance of 15 Ω
B) putting in series a resistance of 240 Ω
C) putting in parallel a resistance of 15 Ω
D) putting in parallel a resistance of 240 Ω
Explanation
[Solution from source] Shunt S = IgG/(I − Ig) = (1 × 60)/(5 − 1) = 15 Ω connected in parallel, so the extra 4 A bypasses the coil. A series resistance would make a voltmeter, not an ammeter. Answer (3).
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.