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The correct OPTION is (B) Drift VELOCITY

Explanation: When the semiconductors like silicon and germanium is implied by an electric field the charge CARRIERS when get drifted by certain velocity known as drift velocity. Drift velocity is PRODUCT of mobility of charge carriers and field intensity.

Correct CHOICE is (a) True

Easiest EXPLANATION: Due to the increase in the reverse saturation CURRENT due to the increase in the temperature, the back resistance decrease with the INCREASING temperature.

Correct choice is (a) True

Explanation: The donor atom donates the EXTRA ION to the SEMICONDUCTOR. Therefore, it is represented by the positive PLUS sign.

Correct OPTION is (a) Junction resistance

Easiest explanation: As the TEMPERATURE of the P-N junction increases the current increases and the voltage DECREASES so the barrier voltage, reverse saturation current, bias current changes with temperature but junction resistance is independent of temperature.

The correct choice is (a) V/I

Explanation: According to Ohms LAW the electric CURRENT in the circuit is DIRECTLY proportion to voltage and INVERSELY proportional to resistance so, R=V/I.

The CORRECT option is (b) EO = Ecp – Ecn

To ELABORATE: The shift in the energy of the energy level will be the difference of the conduction band edge of the p MATERIAL and conduction band edge of n material. In the energy level DIAGRAM, the conduction band edge of p material is higher than that of the n material.

The correct answer is (b) FORWARD direction

To ELABORATE: The P-N junction diode conducts only in forward direction, it will not CONDUCT in reverse direction so only Zener Diode was INTRODUCED as it conducts in both forward and reverse direction.

The correct option is (B) 1

Explanation: Diode is a one junction semiconductor device which has one CATHODE and ANODE. The junction is of p-n type.

Right answer is (b) depletion capacitance increases

To EXPLAIN I would SAY: We know, CT=Aε/W and

W ∝ (1/NA+1/ND)^ 1/2. So, CT∝ (1/NA+1/ND)^-1/2

So when NA and ND increases, depletion capacitance CT increases.

Right answer is (b) REVERSE saturation CURRENT.

Explanation: Reverse saturation current at temperature T2 is 2^[(T2 –T1)/10] times GREATER than reverse saturation current at temperature T1 where T2 is greater than T1.

The CORRECT ANSWER is (d) Resistance

For explanation I would say: I = Io [e^(v/nVt) -1], as shown in this equation the diode current is dependent on temperature , voltage applied on the diode , BOLTZMANN’s constant but diode current is not dependent on resistance as it is INDEPENDENT of resistance.

Right ANSWER is (a) True

Best explanation: In the p region, the drift current is sustained into the p region by the small electric FIELD which is formed at the JUNCTION in the semiconductor. So, the above STATEMENT is true.

The correct ANSWER is (a) True

Easiest EXPLANATION: The net hole current is zero because if this wasn’t true, the hole DENSITY at one END of the semiconductor would continue to increase indefinitely with time, a situation which is obviously physically impossible.

Correct ANSWER is (a) P-region

To EXPLAIN I WOULD say: When the forward biased is APPLIED, the electrons enter to the p-region and the holes enter to the n-region so that holes can FLOW from p-region to n-region. Whereas, the electrons can travel from n-region to p-region.

Right choice is (a) decreasing lifetime and INCREASING ratio of reverse to forward CURRENT

To elaborate: When the current increases the depletion LAYER decreases and the storage and transition time decreases. A decreased depletion layer can EASILY discharge the excess carrier and thereby LESSENS the delay time.

The correct choice is (b) Electron-hole pair

The explanation: As the temperature to the P-N JUNCTION INCREASES the MOBILITY of CHARGES increases thus increases the electron-hole pair which proportionally increases the current in the P-N junction diode.

Correct choice is (c) 1N207

Best explanation: 1N207 is the germanium DIODE for which the REVERSE saturation current is not constant which the CHANGE in voltage due to the LEAKAGE in the surface of the diode and due to the GENERATION of new current carriers.

Correct choice is (c) Resistance

To ELABORATE: When the P-N junction is in forward bias that is the p side connected to the positive terminal of voltage source the current in the circuit can be VARIED by varying the resistance, the current flow decreases as the resistance INCREASES and vice versa.

The correct answer is (a) 0

Easy EXPLANATION: When there is no external voltage applied on the circuit it ACTS as an open circuit and there will be no flow of CHARGES hence the CURRENT and voltage will be zero.

The CORRECT answer is (d) T/11600 VOLTS

Easiest explanation: We KNOW that the P-N junction is TEMPERATURE dependent, it varies with the change in temperature the measure of change that is the voltage equivalent of temperature is given by VT = T/11600 volts.

Right choice is (B) decreases with decreasing CURRENT and increasing temperature

To elaborate: CD =τ I /n0 VT

Where, I is the current and VT is temperature factor. The diffusion CAPACITANCE is DIRECTLY proportional to current and indirectly proportional to the temperature.

Correct option is (B) -5V

Best explanation: At position ‘1’ when connected to +5V, the DIODE is forward biased and ACTS as a short circuit. So, VR is 5V. For 0

Right choice is (b) (VB )^-1/2

Explanation: CT = K/(V0+VB)^1/2

As it’s having uniform doping on both SIDES, the VOLTAGE V0 will be zero. So, CT=K/(VB)^1/2. The variation of TRANSITION capacitance with built in capacitance is (VB )^-1/2.

Right ANSWER is (a) 0 ohms

The EXPLANATION: When the current in the CIRCUIT is zero there will be no flow of CHARGES to resist hence the diode resistance will be zero.

Right ANSWER is (a) 25.8 mV

Explanation: The THERMAL voltage of the diode is given by, VT = KT/Q, by substituting the VALUES of T, K which is Boltzmann constant and q which is the charge of the electron we get VT = (300*1.38*10^-23)/ (1.602*10^-19), VT= 25.8mV.

The CORRECT choice is (a) Exponentially

To EXPLAIN: The current in the VOLT AMPERE CHARACTERISTICS increases exponentially with respect to voltage I(t) = eV(t).

Right option is (a) Ecn – E F = (1/2)*EG – E1

For EXPLANATION: From the energy band diagram of the p-n junction, the option ‘a’ SATISFIES that band diagram.