Avalanche breakdown is due to

In a $P-N$ junction,avalanche current flows in the circuit when the biasing is:

$A$ $2\,V$ battery is connected across $AB$ as shown in the figure. The value of the current supplied by the battery when in one case the battery's positive terminal is connected to $A$ and in the other case when the positive terminal of the battery is connected to $B$ will respectively be:

Which of the following graphs is correct for a $P-N$ junction? (When the $P-N$ junction is forward biased.)

The diode used in the circuit has a barrier voltage of $0.5\,V$ and a maximum power rating of $10\,mW$. What should be the minimum value of resistance $R$ connected in series with the diode?

If the diodes are ideal in the circuit given below,then the current through the cell is (in $A$)