Question

A constant 60 V do supply is connected across two resistors of resistance 400 k$\omega$ 200 k$\omega$. What is the reading of the voltmeter, also of resistance 200 k$\omega$, when connected across the second resistor as shown in figure?

• A. 12 V
• B. 15 V
• C. 20 V
• D. 30 V

Answer 1

The correct option is A 12 V

Given : $E=60$ volts

Equivalent resistance of $200k\Omega$ and $200k\Omega$ connected in parallel, $R^{\prime }=\frac{200\times 200}{200+200}=100k\Omega$

Voltmeter reading $V^{\prime }=\frac{100k\Omega }{100k\Omega +400k\Omega }E=\frac{100}{500}\times 60=12$ volts