10th Class
Science
Electricity and Circuits
Question Bank
Electricity
question_answer
Voltmeters \[{{V}_{1}}\] and \[{{V}_{2}}\] are connected in series across a D.C. line. \[{{V}_{1}}\] reads 80 V and has a per volt resistance of \[200\Omega \], \[{{V}_{2}}\]has a total resistance of\[32\Omega \]. The line voltage is
A) \[120V\]
B) \[160\,V\]
C) \[220\,V\]
D) \[240\,V\]
Correct Answer:
D
Solution :
The circuit is as shown below Here, \[{{R}_{1}}=\]resistance per unit volt\[\times \]total volume \[=200\times 80=16,000=16k\] \[{{R}_{2}}=32k\](given) Now, \[{{V}_{1}}=\left( \frac{V}{{{R}_{1}}+{{R}_{2}}} \right){{R}_{1}}\] or \[V={{V}_{1}}\times \left( \frac{{{R}_{1}}+{{R}_{2}}}{{{R}_{1}}} \right)=\frac{80\times 48}{16}\] \[=80\times 3=\mathbf{240}\]