good

short-circuited

open-circuited

defective

their resistivity is lesser

their barrier potential is higher

their barrier potential is lower

these are lesser temperature sensitive

1 micro A

100 micro A

1 mA

100 mA

threshold voltage

peak inverse voltage

cut-in-voltage

avalanche voltage

they can work both on positive and negative supplies

they consist of both P-type and N-type semiconductor

the conduction of current through them is caused by both 'holes' and 'free electrons'.

of all the three above stated reasons