Title 29. Semiconductor Electronics Materials, Devices And Simple Circuits.pdf ✅

(3) NOT gate (4) XOR gate 14. What will be the input of A and B for the Boolean expression ( A B AB + = ). 1 ( ) (1) 0, 0 (2) 0, 1 (3) 1, 0 (4) 1, 1 15. In a common base transistor circuit, the current gain is 0.98. On changing the emitter current by 5.00 mA, the change in collector current is : (1) 0.196 mA (2) 2.45 mA (3) 4.9 mA (4) 5.1 mA 16. In an n-p-n transistor circuit, the collector current is 10 mA. If 90% of the electrons emitted reach the collector. (1) the emitter current will be 9 mA (2) the emitter current will be 11 mA (3) the emitter current will be 1 mA (4) the base current will be 10 mA. 17. A sinusoidal voltage of peak value 200 volt is connected to a diode and resistor R in the circuit shown, so that half wave rectification occurs. If the forward resistance of the diode is negligible compared to R, the rms value of voltage across R is approximately (in volt) – (1) 200 (2) 100 (3) 100 / 2 (4) 141 18. In a transistor – (1) length of emitter is greater than that of collector (2) length of collector is greater than that of emitter (3) length of base is greater than that of emitter (4) length of base is greater than that of collector 19. Output W is given by – (4) Both (2) and (3) 21. In a p-n junction diode the direction of diffusion current is from - (1) p-region to n-region (2) n-region to p-region (3) n-region to p-region when forward biased and vice-versa when reverse biased (4) p-region to n-region when forward biased and vice-versa when reverse biased 22. Find the current through 1  resistance – (1) 2 amp (2) 1 amp (3) 3 amp (4) None of these 24. Which circuit will not show current in ammeter? 26. A valance breakdown is due to– (1) Collision of minority charge carrier (2) Increase in depletion layer thickness (3) Decrease in depletion layer thickness (4) None of these 27. Which represents NAND gate?
28. Find current through Zener diode– (1) 5 mA (2) 7.5 mA (3) 2.5 mA (4) 12.5 mA 30. In common emitter transistor, current gain is 100 and base current is 2 mA. If load resistance is 0.25  then voltage across load resistance is (1) 5 V (2) 5 mV (3) 50 mV (4) 500 mV 31. In the given circuit The current through the battery is (1) 0.5A (2) 1 A (3) 1.5 A (4) 2 A 32. The current gain  of a transistor is 50. The input resistance of the transistor when used in the common emitter mode is 1 k . the peak value of the collector current for an input peak voltage of 0.01 volt is (1) 0.01 A (2) 0.25 A (3) 100 A (4) 500 A 33. In a semiconductor, (i) there are no free electrons at 0 K (ii) there are no free electrons at any temperature (iii)the number of free electrons increases with temperature (iv) the number of free electrons in semiconductor is less than that in a conductor (1) (i), (ii) (2) (i), (iii), (iv) (3) (ii), (iii) (4) (ii), (iv) 34. The input and the output wave form of a logic gate is shown in diagram, then identify the logic gate :- (1) AND gate (2) OR gate (3) NAND gate (4) NOT gate 35. The energy band diagrams for three semiconductor samples of silicon are as shown. We can then assert that (1) sample X is undoped while samples Y and Z have been doped with a third group and a fifth group impurity respectively (2) sample X is undoped while both samplesY and Z have been doped with a fifth group impurity (3) sample X has been doped with equal amounts of third and fifth group impurities while samples Y and Z are undoped (4) sample X is undoped while samples Y and Z have been doped with a fifth group and a third group impurity respectively 36. In the circuit shown in the figure, if the diode forward voltage drop is 0. 3 V, the volt age difference between A and B is :- (1) 1.3 V (2) 2.3 V (3) 0 V (4) 0.5 V 37. In a n-type semiconductor, which of the following statement is true:
(1) Holes are majority carriers and trivalent atoms are dopants. (2) Electrons are majority carriers and trivalent atoms are dopants. (3) Electron are minority carriers and pantavalent atoms are dopants (4) Holes are minority carriers and pentavalent atoms are dopants. 38. Current in the circuit will be :- 39. Figure gives a system of logic gates. From the study of truth table it can be found that to produce a high output (1) at R, we must have:- (1) X = 0, Y = 1 (2) X = 1, Y = 1 (3) X = 1, Y = 0 (4) X = 0, Y = 0 40. What is the current through an ideal PN- junction diode shown in figure below ? (1) Zero (2) 10 mA (3) 20 mA (4) 50 mA 41. The phase difference between input and output voltage of a CE circuit is : (1) 0° (2) 90° (3) 180° (4) 270° 42. A common emitter amplifier has a voltage gain of 50, an input impedance of 100  and an output impedance of 200  . The power gain of the amplifier is :- (1) 500 (2) 1000 (3) 1250 (4) 100 43 . A NPN transistor conducts when (1) Both collector and emitter are positive with respect to the base (2) Collector is positive and emitter is negative with respect to the base (3) Collector is positive and emitter is at same potential as the base (4) Both collector and emitter are negative with respect to the base 44 . For the transistor circuit shown below if  = 100, Voltage drop between emitter and base is 0. 7 then value of VCE will be (1) 10 V (2) 5 V (3) 13 V (4) 0 V 49. Why is there a sudden increase in current in Zener diode? (1) due to rupture of bonds (2) resistance of depletion layer becomes less (3) due to low doping (4) none of the above 50. Which of the following gates will have an output of 1? 51. An oscillator is nothing but an amplifier with (1) Positive feedback (2) Large gain (3) No feed back (4) Negative feedback 52. Assertion :- A p-n junctions diode is kept in reverse bias while using it as a photodiode. Reason :- Current in forward bias is more than current in reverse bias.