Depletion region in an unbiased semiconductor diode is a region consisting of

The current $I$ in the circuit shown below is: (All diodes are ideal and identical)

If the internal resistance of the cell is negligible,then the current flowing through the circuit is: (in $A$)

What is a depletion barrier?

In an unbiased $n-p$ junction,electrons diffuse from $n-$ region to $p-$ region because

The current-voltage relation of a diode is given by $I = \left( {{e^{\frac{{1000V}}{T}}} - 1} \right) \, mA$,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 $300 \, K$,then the error in the value of the current in $mA$ is.....$mA$