$A$ 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 .......

In a $P-N$ junction diode,if the $P$ region is more heavily doped than the $n$ region,then the depletion layer is:

Which of the following is correct with respect to the following statements? Due to diffusion of electrons from $n$ to $p$-side:
$I$. electrons are accumulated in the depletion region.
$II$. electron drift current is from $p$-side to $n$-side.
$III$. an ionised donor is left in the $n$-region.
$IV$. electrons of $n$-side come to $p$-side and electron-hole combination takes place in $p$-side.
Select the correct option from the following.

In the following circuit,the reading in the ammeter is (in $mA$)

Which of the following statements concerning the depletion zone of an unbiased $PN$ junction is (are) true?
$(A)$ The width of the zone is independent of the densities of the dopants (impurities).
$(B)$ The width of the zone is dependent on the densities of the dopants.
$(C)$ The electric field in the zone is produced by the ionized dopant atoms.
$(D)$ The electric field in the zone is provided by the electrons in the conduction band and the holes in the valence band.

Write a short note on a semiconductor diode.