Q. A milliammeter of range 0-30mA has internal resistance of 20$\ \Omega$. The resistance to be connected in series to convert it into a voltmeter of maximum reading 3V is
A) 49$\ \Omega$
B) 80$\ \Omega$
C) 40$\ \Omega$
D) 30$\ \Omega$
Explanation
(b) $R = \frac{V}{I_{g}} - G = \frac{3}{30 \times 10^{- 3}} - 20 = 10^{2} - 20 = 80\Omega$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.