What is the type of bias b/w CB and EB for normal operation?

What is a Zener diode? How is it biased in normal operation?

What is a zener diode how is it biased in normal operation

In normal transistor operation

In normal transistor operation-

The current in the forward bias is known to be more (mA) than the current in the reverse bias ( ~ mu A). What is the reason, then why photo diodes is to operate in reverse bias.

In a normal operation of a transistor,

In a normal operation of a transistor,