Physics Semiconductor Devices

 Suppose a pure Si crystal has $5*{10}^{28}$ atoms $/{\mathrm{m}}^3$ . It is doped by $1\mathrm{p}\mathrm{p}\mathrm{m}$ concentration of pentavalent As. The number of holes $\left(n_i=1.5*{10}^{16}/{\mathrm{m}}^3\right)$  is:

The photodiode is used to detect the optical signals. These diodes are preferably operated in reverse biased mode because:

Given below are two statements:

Statement I: Photovoltaic devices can convert optical radiation into electricity.

Statement II: Zener diode is designed to operate under reverse bias in breakdown region.

In the light of the above statements, choose the most appropriate answer from the options given below:

A full wave rectifier circuit consists of two p-n junction diodes, a centre-tapped transformer, capacitor and a load resistance. Which of these components remove the ac ripple from the rectified output

In half wave rectification, if the input frequency is $60\mathrm{H}\mathrm{z}$ , then the output frequency would be :

In the given circuits (a), (b) and (c), the potential drop across the two p-n junctions are equal in :

An npn transistor operates as a common emitter amplifier with a power gain of 10?. The input circuit resistance is 100Ω and the output load resistance is 10kΩ. The common emitter current gain 'β' will be -----------. (Round off to the Nearest Integer)

With increasing biasing voltage of a photodiode, the photocurrent magnitude:

Boolean relation at the output state-Y for the following circuits is: