Question

Two resistors of resistances $200\,k\Omega$ and $1\,M\Omega$ respectively form a potential divider with outer junctions maintained at potentials of $+3V$ and $-15V$ . Then, the potential at the junction between the resistors is

• A. $+1\text{ }V$
• B. $-0.6\text{ }V$
• C. zero
• D. $-\,12V$

Answer 1

Answer: (C)

zero

Answer 2

Current $i=\frac{{{V}_{1}}-{{V}_{2}}}{{{R}_{1}}+{{R}_{2}}}=\frac{18}{1.2\times {{10}^{-6}}}$
V across $1\,M\Omega =\frac{18}{1.2\times {{10}^{-6}}}\times 1\times {{10}^{-6}}$
$=15\,V$
$\therefore$ Potential at $P=15-15=0$