Which is the primary constitutional unit for diode and transistor?

The circuit has two oppositely connected ideal diodes in parallel. What is the current flowing in the circuit (in $A$)?

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

In the given figure,each diode has a forward bias resistance of $30\, \Omega$ and infinite resistance in reverse bias. The current ${I}_{1}$ will be $....\,A$.

Show the direction of the electric field that arises in a $p-n$ junction.

$A$ device is connected to a supply such that one end is connected to the positive terminal and the other to the negative terminal. If the connections are reversed and no current flows,the device is a .......