Semi conductor devices practice · Medium

Statement-I: In Zener diode depletion layer is thin.

Statement-II: In reverse bias, strong electric field exists across the potential barrier.

Carbon, silicon and germanium atoms have four valence electrons each. Their valence and conduction bands are separated by energy band gaps represented by $\left(E_g\right)_{{C}},\left(E_g\right)_{{Si}}$ and $\left(E_g\right)_{{Ge}}$, respectively. Which one of the following relationship is true in their case?

Metallic solids are always opaque because

Choose the correct statement

In which of the following ionic bond is present

A semiconductor device is connected in a series circuit with a battery and a resistance. A current is found to pass through the circuit. If the polarity of the battery is revered, the current drops almost to zero. The device may be

Statement I: By doping silicon semiconductor with pentavalent material the electrons density increases.
Statement II: The $n$-type semiconductor has net negative charge.
In the light of the above statements choose the most appropriate answer from the options given below.

Assertion: Electron has higher mobility than hole in a semiconductor.
Reason: Mass of electron is less than the mass of hole

Semiconductor is damaged by the strong current due to

When the forward bias voltage of a diode is changed from 0.6 V to 0.7 V, the current changes from 5 mA to 15 mA. Then its forward bias resistance is

In the study of transistor as an amplifier, if $\alpha = {I_c}/{I_e}$ and $\beta = {I_c}/{I_b}$, where ${I_c},{I_b}$ and ${I_e}$ are the collector, base and emitter currents, then

A half wave rectifier is used to convert 80 Hz A.C into D.C voltage the number of pulses per second in the rectified voltage are

In a solar cell current is generated due to bond breakage in
which region.

When a battery is connected to a $P$-type semiconductor with a metallic wire, the current in the semiconductor (predominantly), inside the metallic wire and that inside the battery respectively is due to

Assertion : In solar cell it is imperative (essential) that photo generation of electrons and holes occurs in depletion region.

Reason : The junction Field separates electron hole pair effectively.

In a junction diode, the direction of diffusion current is

Zener diode is used as

In a P-type semiconductor, the acceptor impurity produces an energy level

Diode valve is discovered by

LED is a $p$-$n$ junction diode which is

To measure light intensity we use

If $\mathrm{\alpha \;and\;\beta }$ are the collector emitter short circuit current amplification factor and collector base short circuit current amplification factor respectively of a transistor then $\mathrm{\alpha }$ is equal to

The peak voltage in the output of a half wave diode rectifier fed with a sinusoidal signal without filter is $10 \, {~V}$. The D.C. component of the output voltage is :

In a semiconductor

Avalanche breakdown of p-n junction diode is due to

In a $P$-type semiconductor

Which of the following statements are CORRECT?

Statement I: When a battery is connected across the junction diode with its negative terminal connected to the p-side and the positive terminal connected to the $\mathrm{n}$-side, the diode is said to be forward biased.

Statement II: In forward bias condition, if the bias voltage is greater than the barrier potential, the majority carries move towards the junction and cross it.

Statement III: In reverse biasing of a diode, the majority carriers are pulled away from the junction, making the depletion layer wider.

Assertion: Positive feedback is essential for converting a transistor into an oscillator.
Reason: Positive feedback works between cut-off and saturation region.

The saturation current in a diode valve is governed by

The conductivity of an intrinsic semiconductor depends on temperature as $\sigma=\sigma_0 e^{-\Delta E / 2 k T}$, where $\sigma_0$ is a constant. Find the temperature at which the conductivity of an intrinsic germanium semiconductor will be double of its value at $T=300 \mathrm{~K}$. Assume that the gap for germanium is $0.650 \mathrm{~eV}$ and remains constant as the temperature is increased.