A power supply is being compared with a solar cell by means of the potentiometer circuit shown. The e.m.f. of the solar cell is obtained with the potentiometer. The potentiometer wire $PQ$ has a length of $100.0\,\text{cm}$ and a resistance of $5.00\,\Omega$. The power supply has an e.m.f. of $2.000\,\text{V}$, while the solar cell has an e.m.f. of $5.00\,\text{mV}$. Which resistance $R$ should be used so that the galvanometer gives a zero reading when $PS = 40.0\,\text{cm}$?
- A$395\,\Omega$
- B$795\,\Omega$
- C$995\,\Omega$
- D$1055\,\Omega$