The solids which have the negative temperature coefficient of resistance are:

For transistor action, which of the following statements is correct?

In an n-type silicon, which of the following statement is true:

Carbon, silicon, and germanium have four valence electrons each. These are characterized by valence and conduction bands separated by the energy bandgap respectively equal to (Eg)C, (Eg)Si, and (Eg)Ge. Which of the following statements is true?

In an unbiased p-n junction, holes diffuse from the p-region to n-region because

When a forward bias is applied to a p-n junction, it

For a transistor amplifier, the voltage gain

In a half-wave rectification, what is the output frequency if the input frequency is 50 Hz?

For a CE-transistor amplifier, the audio signal voltage across the collector resistance of 2 kΩ is 2 V. Suppose the current amplification factor of the transistor is 100, what is the base current if the base resistance is 1 kΩ?

$$\begin{gathered} \left(1\right) 14 \mu A \\ \left(2\right) 12 \mu A \\ \left(3\right) 15 \mu A \\ \left(4\right) 10 \mu A \end{gathered}$$

Two amplifiers are connected one after the other in series (cascaded). The first amplifier has a voltage gain of 10 and the second has a voltage gain of 20. If the input signal is 0. 01 volt, the output ac signal is:

A p-n photodiode is fabricated from a semiconductor with a bandgap of 2.8 eV. The energy of the incident photon with a waveength of 6000 nm is:

The number of silicon atoms per m³ is 5 × 10²⁸. This is doped simultaneously with 5 × 10²² atoms per m³ of Arsenic and 5 × 10²⁰ per m³ atoms of Indium. The number of holes is: (Given that $n_i=1.5\times {10}^{16} m^{-3}$)

$$\begin{gathered} \left(1\right) 4.51\times {10}^9 \\ \left(2\right) 4.99\times {10}^{22} \\ \left(3\right) 1.56\times {10}^{22} \\ \left(4\right) 3.33\times {10}^{23} \end{gathered}$$

An n-p-n transistor is connected in a common emitter configuration (see figure) in which collector voltage drop across load resistance ( 800 $\Omega$ ) connected to the collector circuit is 0.8 V. The collector current is : 

Which of the following gate is called universal gate? 

An intrinsic semiconductor is converted into an n-type extrinsic semiconductor by doping it with: 

C, Si, and Ge have the same lattice structure. Why is the C insulator?

In an intrinsic semiconductor, the energy gap Eg is 1.2eV. Its hole mobility is much smaller than electron mobility and independent of temperature. What is the ratio between conductivity at 600K and that at 300K? Assume that the temperature dependence of intrinsic carrier concentration $n_i$ is given by, 

${\mathrm{n}}_{\mathrm{i}}={\mathrm{n}}_0\exp \left[\frac{-{\mathrm{E}}_{\mathrm{g}}}{2{\mathrm{K}}_{\mathrm{B}}\mathrm{T}}\right] \mathrm{where} {\mathrm{n}}_0 \mathrm{is} \mathrm{a} \mathrm{constant}.$

$$\begin{gathered} \left(1\right) 1.01\times {10}^6:1 \\ \left(2\right) 1.09\times {10}^5:1 \\ \left(3\right) 1:1 \\ \left(4\right) 1:2 \end{gathered}$$

Which statement is true for the given circuit:

A NAND gate connected as given in the figure,

The circuit operates like a:

In the figure given below, assuming the diodes to be ideal,
                      

A 220 V AC supply is connected between points A and B (figure). What will be the potential difference V across the capacitor?

Hole is:

The output of the given circuit in figure given below,

In the circuit shown in the figure given below, if the diode forward voltage drop is 0.3 V, the voltage difference between A and B is:

Truth table for the given circuit is:

In the depletion region of a diode:

(a) there are no mobile charges
(b) equal number of holes and electrons exist, making the region neutral
(c) recombination of holes and electrons has taken place
(d) immobile charged ions exist

What happens during the regulation action of a Zener diode?

(a) The current and voltage across the Zener remain fixed
(b) The current through the series Resistance (R_s) changes
(c) The Zener resistance is constant
(d) The resistance offered by the Zener changes

To reduce the ripples in rectifier circuit with capacitor filter:

(a) R_L should be increased
(b) input frequency should be decreased
(c) input frequency should be increased
(d) capacitors with high capacitance should be used