Question

In the circuit shown in the figure $V_1$ and $V_2$ are two voltmeters of resistance $3000\Omega$ and $2000\Omega$ respectively. $R_1=2000\Omega$ and $R_2=3000\Omega$. A is an ideal ammeter consider both cases i.e. switch S open or switch S closed to match the readings. The cell is ideal. Ammeter $\left(A_1\right)$ and $\left(A_2\right)$ are also ideal :

• A. Reading of voltmeter $V_1$ in volt may be 120 Volt
• B. Reading of voltmeter $V_1$ in volt may be 100 Volt
• C. Reading of ammeter A may be 100 miliampere
• D. Reading of ammeter $A_1$ may be 50 milliampere

Answer 1

The correct option is D Reading of ammeter $A_1$ may be 50 milliampere

S open, (see image 1)
$V_1+V_2=E=200\frac{V_1}{V_2}=\frac{3}{2}$
$V_1=\frac{3}{5}\times 200=120V,V_2=80V$
$i=\frac{E}{2500}=\frac{200}{2500}\times 1000mA=80mA$
S closed (image 2)
$A=\frac{1}{12}Amp.;V_1=V_2=100V$
$A_1=\frac{3}{60}A=50mA;A_2=\frac{2}{60}A=\frac{100}{3}$