Choose the correct option for the forward biased characteristics of a $p\text{–}n$ junction.

A diode is made forward biased by a two volt battery. However, there is a drop of $0.5 \mathrm{V}$ across the diode which is independent of current. Also, a current greater than $10 \mathrm{mA}$ produces large joule loss and damages the diode. If diode is to be operated at $5 \mathrm{mA}$, the series resistance to be put is,

For given circuit, the potential difference $V_{\mathrm{AB}}$ is,

Refer to the circuit given below. The output voltage $V_0$ is measured between points $a$ and $b$. Then,