The reason for current flow in a $P-N$ junction in forward bias is

When no bias is applied to a $P-N$ junction,the current is:

In the given circuits,which diode is in forward bias?

The current-voltage relation of a diode is given by $I = (e^{1000V/T} - 1) \; mA$,where the applied voltage $V$ is in volts and the temperature $T$ is in Kelvin. If a student makes an error of $\pm 0.01 \; V$ while measuring the voltage to obtain a current of $5 \; mA$ at $300 \; K$,what will be the error in the value of the current in $mA$?

If the forward voltage in a diode is increased,the width of the depletion region $\qquad$ .

$P-N$ junction is said to be forward biased,when