Question

In the given circuit voltmeter shows a reading of $4V$, then the power developed across $R$ resistance will be

• A. $15mW$
• B. $14mW$
• C. $12mW$
• D. $10mW$

Answer 1

The correct option is C $12mW$

Supply voltage $=V_1$ (through resistor of $2K\Omega )+V_2$ (through volt meter)

$10V=V_1+4V$

$\therefore V_1=10V-4V=6V$

$V=RI$

$\therefore 6=1\times 2000$

$I=\frac{6}{2000}=3mA$

Power developed across $R$,

$P=V_2\times I=4\times 3mW=12mW$