Question

Voltmeters $V_{1}$ and $V_{2}$ are connected in series across a D.C. line. $V_{1}$ reads $80$ volts and has a per volt resistance of $200$ ohms. $V_{2}$ has a total resistance of $32$ kilo-ohms. The line voltage is

• A. 120 volts
• B. 160 volts
• C. 220 volts
• D. 240 volts

Answer 1

Answer: (D)

$R_{1}=80 \times 200=16000\, \Omega=16 \,k \Omega$
Current flowing through $V_{1}=$ Current flowing through
$V_{2}=\frac{80}{16 \times 10^{3}}=5 \times 10^{-3} A$
So, potential difference across $V_{2}$ is
$V_{2}=5 \times 10^{-3} \times 32 \times 10^{3}=160 \text { volt }$
Hence, line voltage, $V=V_{1}+V_{2}$
$=80+160=240\, V$