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![[Post New]](/templates/default/images/icon_minipost_new.gif) 3 Mar 2008 06:46:11 IST
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| Q.1) Define forbidden gap. | | ( 1 mark ) | View Answer
| (Q.2) How does the energy gap in an intrinsic semiconductor change, when doped with a trivalent impurity? | | ( 1 mark ) | View Answer
| (Q.3) Out of electrons and holes, which has higher mobility? | | ( 1 mark ) | View Answer
| (Q.4) What is depletion region in a p-n junction? | | ( 1 mark ) | View Answer
| (Q.5) Which special type of diode can act as a voltage regulator? Give the symbol of this diode and draw the general shape of its V-I characteristics. | | ( 1 mark ) | View Answer
| (Q.6) Draw the logic symbol of two input NOR gate. Write down its truth table. | | ( 1 mark ) | View Answer
| (Q.7) What do you mean by rectification? | | ( 1 mark ) | View Answer
| (Q.9) What is meant by the term doping? | | ( 1 mark ) | View Answer
| (Q.12) Which of the following truth table represents an AND gate? | | ( 1 mark ) | (A) | (a) | Input | Output | | | | A | B | Y | | | | 0 | 0 | 0 | | | | 0 | 1 | 1 | | | | 1 | 0 | 1 | | | | 1 | 1 | 1 | | (B) | | Input | Output | | | A | B | Y | | | 0 | 0 | 1 | | | 0 | 1 | 1 | | | 1 | 0 | 1 | | | 1 | 1 | 0 | (C) |
| Input | Output | | | | A | B | Y | | | | 0 | 0 | 0 | | | | 0 | 1 | 0 | | | | 1 | 0 | 0 | | | | 1 | 1 | 1 | | (D) |
| Input | Output | | | A | B | Y | | | 0 | 0 | 1 | | | 0 | 1 | 0 | | | 1 | 0 | 0 | | | 1 | 1 | 0 | View Answer
| (Q.13) In the Boolean algebra, which of the following is wrong? | | ( 1 mark ) | (A) 1 + 0 = 1(B) 0 + 1 = 1 (C) 1 + 1 = 1 (D) 1 + 1 = 0View Answer
| (Q.14) In a common base transistor circuit the current gain is 0.92 on changing emitter current by 8.00 mA, the change in collector current is | | ( 1 mark ) | (A) 2.415 mA(B) 7.36 mA(C) 8.00 mA (D) 0.92 mAView Answer
| (Q.15) Which of the following gate is considered as a universal gate? | | ( 1 mark ) | (A) NOR gate(B) AND gate (C) NOT gate(D) OR gateView Answer
| (Q.16) The output of a gate is '1' only when both inputs are '0'. The gate must be a | | ( 1 mark ) | (A) OR gate(B) AND gate (C) NOR gate(D) NAND gateView Answer
| (Q.17) If a zener diode (Vz = 10V, Iz = 10 mA) is connected in series with a resistance and 20 V is applied across the combination, then the maximum resistance one can use without spoiling zener action is | | ( 1 mark ) | (A) 1 k W (B) 4 kW (C) 2 kW (D) 3 kW View Answer
| (Q.18) The current gain of a transistor is 100. If the base current changes by 200 mA. What will be the change in collector current? | | ( 1 mark ) | (A) 200 mA (B) 20 mA (C) 2 mA(D) 0.2 mAView Answer
| (Q.19) The majority charge carriers in a p-type semiconductor are | | ( 1 mark ) | (A) Electrons (B) Holes (C) Neutrons(D) PhotonsView Answer
| (Q.20) Which of the following is correct regarding a p-type semiconductor? | | ( 1 mark ) | (A) It is an intrinsic semiconductor(B) It has pentavalent impurity(C) It has tetravalent impurity(D) None of theseView Answer
| (Q.21) If nh and ne are hole and electron concentrations then for an n-type semiconductor | | ( 1 mark ) | (A) 
(B) nh = ne(C)
(D) nh = ne = 0View Answer
| (Q.22) A solar cell is basically | | ( 1 mark ) | (A) A p-type semiconductor(B) An n-type semiconductor(C) A p-n junction (D) None of theseView Answer
| (Q.23) Which of the following graph represents the I-V characteristics of a zener diode? | | ( 1 mark ) | (A) (B) (C)
(D) View Answer
| (Q.24) Which of the following is wrong for a transistor? | | ( 1 mark ) | (A) The ratio of change in collector-emitter voltage (DVCE) to the change in collector current (DIC) at a constant base current IB is called output resistance (r0).(B) The ratio of change in base-emitter voltage (DVBE) to the resulting change in base current (DIB) at constant collector-emitter voltage (VCE) is known as input resistance (ri).(C) The ratio of change in base current to the change in collector current is defined as the current amplification factor (b).(D) A transistor acts as an amplifier when operated in the active regionView Answer
| (Q.25) In case of half wave rectifier circuit operating from 100 Hz main frequency, the fundamental frequency in the ripple would be | | ( 1 mark ) | (A) 50 Hz(B) 25 Hz(C) 200 Hz(D) 100 HzView Answer
| (Q.26) When the reverse potentials in the semiconductor diode are 10 V and 50 V, the corresponding reverse currents are 100 mA to 300 mA respectively. The reverse resistance of junction diode will be | | ( 1 mark ) | (A)  (B)  (C)  (D)  View Answer
| (Q.27) If the forward bias on p-n junction is increased from zero to 0.095 V, then no currunt flows in the circuit. The contact potential of junction plane is | | ( 1 mark ) | (A) Zero (B) 0.095 V(C) More than 0.095 V (D) Less than 0.95 VView Answer
| (Q.28) In case of p-n-junction diode, at zener voltage the current rises sharply. It happens because of | | ( 1 mark ) | (A) High value of reverse bias (B) Very low value of reverse bias(C) Very high value of forward bias(D) No reverse bias at allView Answer
| (Q.29) If A = 1 and B = 0, then in terms of Boolean algebra what is the value of A.A + B? | | ( 1 mark ) | (A) B + A(B) A(C) B(D) A2 + B View Answer
| (Q.30) Which of the following is not true in Boolean algebra? | | ( 1 mark ) | (A)  (B)  (C)  (D)  View Answer
(Q.31) A transistor has an  then b is equal to | | ( 1 mark ) | (A) 0.95 (B) 1.5 (C) 19 (D)  View Answer
(Q.32) Consider a two-input AND gate of figure below. Out of the four entries for the truth table given here the correct ones are | | A | B | C | | 1. | 0 | 1 | 0 | | 2. | 1 | 0 | 0 | | 3. | 1 | 1 | 1 | | 4. | 0 | 0 | 1 | | | ( 1 mark ) | (A) All (B) 1 and 2(C) 1, 2 and 3(D) 1, 3 and 4View Answer
(Q.33) What is the value of output voltage  in the circuit below | | ( 1 mark ) | (A) 6 V(B) 14 V(C) 42 V (D) 7 VView Answer
| (Q.34) The output of the logic circuit shown in the figure below is best represented by which of the following options | | ( 1 mark ) | (A)  (B)  (C)  (D) | |
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