The energy of a photon in a monochromatic light of wavelength $621 \ nm$ matches with the band gap of a semiconducting material. Then the minimum energy required to create an electron-hole pair from the semiconductor is
[Take $hc = 1242 \ eV-nm$,where $h$ is Planck's constant and $c$ is speed of light in vacuum] (in $eV$)

Consider a $p-n$ junction as a capacitor,formed with $p$ and $n$-materials acting as thin metal electrodes and depletion layer width acting as separation between them. Basing on this,assume that an $n-p-n$ transistor is working as an amplifier in $CE$ configuration. If $C_1$ and $C_2$ are the base-emitter and collector-emitter junction capacitances,then :

Which of the following circuits is in forward bias?

The width of the depletion layer of a $p-n$ junction diode,when it is $(i)$ forward biased and $(ii)$ reverse biased,respectively,is:

The reading of the ammeter for a silicon diode in the given circuit is ....... $mA$.

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