Q. A galvanometer having a coil resistance of $60\ \Omega$ 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 parallel a resistance of $240\ \Omega$
B) Putting in series a resistance of $15\ \Omega$
C) Putting in series a resistance of $240\ \Omega$
D) Putting in parallel a resistance of $15\ \Omega$
Explanation
(d) $\frac{i}{ig} = 1 + \frac{G}{S} \Rightarrow \frac{5}{1} = 1 + \frac{60}{S} \Rightarrow S = 15\Omega$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.