Q. Voltmeters $V_{1}$and $V_{2}$ are connected in series across a DC line. $V_{1}$reads 80V and has a resistance of $200\Omega V^{- 1}and\ V_{2}$ has a total resistance of 32k$\ \Omega$. The line voltage is
A) 240 V
B) 220 V
C) 160 V
D) 120 V
Explanation
(a) Resistance of $V_{1} = 80 \times 200$
=16000$\Omega$
Resistance of $V_{2}$=32000$\Omega$
The current flowing in the circuit is given by
$\ \ \ \ \ \ \ \ \ \ i = \frac{80}{16000} = \frac{1}{200}A$
Total resistance of the circuit
=16000+32000=48000$\Omega$
Line voltage$= iR$
$= \frac{48000}{200} = 240V$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.