The breakdown in a reverse-biased p-n junction is more likely to occur due to 

(a) the large velocity of the minority charge carriers if the doping concentration is small
(b) the large velocity of the minority charge carriers if the doping concentration is large
(c) strong electric field in a depletion region if the doping concentration is small
(d) strong electric field in the depletion region if the doping concentration is large

Out of the following which one is a forward-biased diode? 

Suppose a pure Si crystal has $5\times {10}^{28} \mathrm{atoms} {\mathrm{m}}^{-3}.$  It is doped by a 1 ppm concentration of pentavalent As. The number of electrons and holes are, respectively: $\left(\mathrm{Given} \mathrm{that} {\mathrm{n}}_{\mathrm{i}}=1.5\times {10}^{16} {\mathrm{m}}^{-3}\right)$

$$\begin{gathered} 1. 5\times {10}^{22}/{\mathrm{m}}^3, 4.5\times {10}^9/{\mathrm{m}}^3 \\ 2. 4.5\times {10}^9/{\mathrm{m}}^3, 5\times {10}^{22}/{\mathrm{m}}^3 \\ 3. 5\times {10}^{22}/{\mathrm{m}}^3, 5\times {10}^{22}/{\mathrm{m}}^3 \\ 4. 4.5\times {10}^9/{\mathrm{m}}^3, 4.5\times {10}^9/{\mathrm{m}}^3 \end{gathered}$$ 

Why can't we take one slab of p-type semiconductor and physically join it to another slab of n-type semiconductor to get a p-n junction?

The V-I characteristic of a silicon diode is shown in the figure. The resistance of the diode at ${\mathrm{I}}_{\mathrm{D}}=15 \mathrm{mA}$ is: 

$$\begin{gathered} 1. 20 \mathrm{\Omega } \\ 2. 30 \mathrm{\Omega } \\ 3. 15 \mathrm{\Omega } \\ 4. 10 \mathrm{\Omega } \end{gathered}$$

The V-I characteristic of a silicon diode is shown in the figure. The resistance of the diode at ${\mathrm{V}}_{\mathrm{D}}=-10 \mathrm{V}$ is: 

$$\begin{gathered} 1. 1\times {10}^7 \mathrm{\Omega } \\ 2. 2\times {10}^7 \mathrm{\Omega } \\ 3. 3\times {10}^7 \mathrm{\Omega } \\ 4. 4\times {10}^7 \mathrm{\Omega } \end{gathered}$$

In a Zener regulated power supply, a Zener diode with ${\mathrm{V}}_{\mathrm{Z}}$= 6.0 V is used for regulation. The load current is to be 4.0 mA and the unregulated input is 10.0 V. The value of the series resistor ${\mathrm{R}}_{\mathrm{S}}$ will be:$\left(\mathrm{Assume} {\mathrm{I}}_{\mathrm{Z}}=5{\mathrm{I}}_{\mathrm{L}}\right)$

$$\begin{gathered} 1. \mathrm{Less} \mathrm{than} 100 \mathrm{\Omega } \\ 2. \mathrm{Zero} \\ 3. \mathrm{Infinite} \\ 4. 150 \mathrm{\Omega } \end{gathered}$$

Which one of the following is not true for the photodiodes?

The diagram shows graph of current versus voltage for a material. The material can be a:

Which material is preferred for solar cells?

Graph shows barrier potential for a p-n junction diode under different biasing conditions where V_o is the built-in potential of the diode. Then graph 2 represents:

The output characteristics of a transistor are shown in the figure. When $V_{CE}$ is 10 V and $I_C$  = 4.0 mA, the value of ${\beta }_{ac}$ is:

1. The output waveform (Y) of the AND gate for the following inputs A and B given in the figure is:

The output waveform (Y) of the NAND gate for the following inputs A and B given in the figure is:

For a Silicon CE transistor amplifier, the audio signal voltage across the collector resistance of 2.0 k$\Omega$ is 2.0 V. Suppose the current amplification factor of the transistor is 100, what should be the value of ${\mathrm{R<strong>_B</strong>}}_{}$ in series with the supply of 2.0 V if the dc base current has to be 10 times the signal current?

$$\begin{gathered} 1. 18 k\Omega \\ 2. 16 k\Omega \\ 3. 12 k\Omega \\ 4. 14 k\Omega \end{gathered}$$

For a Silicon CE transistor amplifier, the audio signal voltage across the collector resistance of 2.0 k$\Omega$ is 2.0 V. Suppose the current amplification factor of the transistor is 100 if the dc base current has to be 10 times the signal current. The dc current across through the collector resistance will be:

In figure, the $V_{BB}$ supply can be varied from 0 V to 5.0 V. The Si transistor has ${\beta }_{dc}$ = 250 and $R_B$= 100 k$\Omega$, $R_C$ = 1 K$\Omega$, $V_{CC}$= 5.0 V. Assume that when the transistor is saturated, $V_{CE}$ = 0 V and $V_{BE}$= 0.8V. The minimum base current, for which the transistor will reach saturation is:

 $$\begin{gathered} 1. 20 \mu A \\ 2. 5 mA \\ 3. 20 mA \\ 4. 5 \mu A \end{gathered}$$

In figure, the $V_{BB}$ supply can be varied from 0 V to 5.0 V. The Si transistor has ${\beta }_{dc}$ = 250 and $R_B$= 100 k$\Omega$, $R_C$ = 1 K$\Omega$, $V_{CC}$= 5.0 V. Assume that when the transistor is saturated, $V_{CE}$ = 0 V and $V_{BE}$= 0.8V. The input voltage for which the transistor will reach saturation is:

The electron concentration in an n-type semiconductor is the same as hole concentration in a p-type semiconductor. An external field (electric) is applied across each of them. Compare the currents in them.

Consider the following statements (A) and (B) and identify the correct answer. 

A. A zener diode is connected in reverse bias when used as a voltage regulator.

B. The potential barrier of p-n junction lies between 0.2 V to 0.3 V.

For the given circuit, the input digital signals are applied at the terminals A, B and C. What would be the output at the terminal y?

When a diode is forward biased, it has a voltage drop of 0.5 V. The safe limit of current through the diode is 10 mA. If a battery of emf 1.5 V is used in the circuit, the value of minimum resistance to be connected in series with the diode so that the current does not exceed the safe limit is-