$A$ 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 .......

When a $p-n$ diode is reverse biased,then

Statement $I :$ When a $Si$ sample is doped with Boron,it becomes $P$-type and when doped by Arsenic it becomes $N$-type semiconductor such that $P$-type has excess holes and $N$-type has excess electrons.
Statement $II$ : When such $P$-type and $N$-type semiconductors are fused to make a junction,a current will automatically flow which can be detected with an externally connected ammeter.
In the light of above statements,choose the most appropriate answer from the options given below.

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

In a $p-n$ junction diode, the thickness of the depletion layer is $2 \times 10^{-6} \,m$ and the barrier potential is $0.3 \,V$. The intensity of the electric field at the junction is

In the reverse biasing of a $p-n$ junction diode,