Title 14. SEMICONDUCTOR ELECTRONICS- MATERIALS- DEVICES AND SIMPLE CIRCUITS.pdf ✅

tance at constant base current of (1) (2) (3) (4) 19. Assertion : An -type semiconductor has a large number of electrons but still it is electrically neutral. Reason : An -type semiconductor is obtained by doping an intrinsic semiconductor with a trivalent impurity. (1) Both Assertion and Reason are cor- rect and Reason is the correct explana- tion of the Assertion. (2) Both Assertion and Reason are cor- rect but Reason is not the correct explana- tion of the Assertion. (3) Assertion is cor- rect but Reason is incorrect. (4) Assertion is incor- rect but reason is correct. 20. Two ideal diodes connected as shown in the fig‐ ure. The current flowing through the resis‐ tance will be (1) (2) (3) (4) 21. In half wave rectification, if the input frequency is 60 , then the output frequency would be (1) (2) (3) (4) 22. The output of the given logic gate is similar to the output of an/a (1) NAND gate (2) NOR gate (3) OR gate (4) AND gate 23. Assertion : In a transistor amplifier (in common emitter con‐ figuration), the output voltage is always out of phase with the input voltage. Reason : The emitter base junction is reverse biased and the base collector junction is forward biased. (1) Both Assertion and Reason are cor- rect and Reason is the correct explana- tion of the Assertion. (2) Both Assertion and Reason are cor- rect but Reason is not the correct explana- tion of the Assertion. (3) Assertion is cor- rect but Reason is incorrect. (4) Assertion is incor- rect but reason is correct. 24. In the following circuit the output becomes zero for the inputs (1) (2) (3) (4) 25. In the given circuit, the voltage across load re‐ sistance is (1) (2) (3) (4) 26. Two similar - junctions can be connected in three different ways as shown in the figures. The two connections across which the potential dif‐ ference is same are (1) Circuits and (2) Circuits and (3) Circuits and (4) All the circuits 27. Assertion : When a semiconductor is doped with a donor im‐ purity, the hole concentration decreases and the 60μA 3.14 kΩ 120 kΩ 15 kΩ 5.4 kΩ N N R2 0.5 A 3 A 2 A 1.25 A Hz 30 Hz 60 Hz 120 Hz Zero (Y ) Y A = 1, B = 0, C = 0 A = 0, B = 1, C = 1 A = 0, B = 0, C = 0 A = 1, B = 1, C = 0 (RL) 14.00 V 9.00 V 8.50 V 8.75 V p n A B B C A C
electron concentration increases. Reason : A donor impurity is an atom with valence elec‐ trons of five always. (1) Both Assertion and Reason are cor- rect and Reason is the correct explana- tion of the Assertion. (2) Both Assertion and Reason are cor- rect but Reason is not the correct explana- tion of the Assertion. (3) Assertion is cor- rect but Reason is incorrect. (4) Assertion is incor- rect but reason is correct. 28. Assertion : Photodiode and solar cell works on same mecha‐ nism Reason : Area is large for solar cell. (1) Both Assertion and Reason are cor- rect and Reason is the correct explana- tion of the Assertion. (2) Both Assertion and Reason are cor- rect but Reason is not the correct explana- tion of the Assertion. (3) Assertion is cor- rect but Reason is incorrect. (4) Both Assertion and Reason are incorrect. 29. Assertion : Two junction diodes placed back to back, will work as a transistor. Reason : The -region of two junction diodes back to back will form the base of transistor. (1) Both assertion and reason are cor- rect and reason is the correct explanation of assertion. (2) Both assertion and reason are cor- rect but reason is not the correct explana- tion of assertion. (3) Assertion is cor- rect but reason is incorrect. (4) Assertion is incor- rect but reason is correct. 30. Symbolic representation of four logic gates are shown as Pick out which ones are for AND, NAND and NOT gates, respectively. (1) ( ), ( ) and ( ) (2) ( ), ( ) and ( ) (3) ( ), ( ) and ( ) (4) ( ), ( ) and ( ) 31. Choose the only false statement from the following. (1) Substances with energy gap of the or- der of are insulators. (2) The conductivity of a semiconductor increases with in- crease in temperature. (3) In conductors, the valence and conduc- tion bands may overlap. (4) The resistivity of a semiconductor in- creases with increase in temperature. 32. Statement A : If the temperature of a semiconductor is in‐ creased then its resistance decreases. Statement B : The energy gap between conduction band and valence band is 10 in semiconductors. (1) Statement A is correct but Statement B is incorrect. (2) Statement A is in- correct but Statement B is correct. (3) Both Statements are correct. (4) Both Statements are incorrect. 33. Assertion : In common base configuration, the current gain of the transistor is less than unity. Reason : The collector terminal is reverse biased for amplication. (1) Both Assertion and Reason are cor- rect and Reason is the correct explana- tion of the Assertion. (2) Both Assertion and Reason are cor- rect but Reason is not the correct explana- tion of the Assertion. (3) Assertion is cor- rect but Reason is incorrect. (4) Assertion is incor- rect but reason is correct. 34. The equivalent of 110 in the decimal number is (1) (2) (3) (4) 35. Negative feedback (1) Increases stability (2) Decreases stability (3) Produces rectification (4) None of these 36. In the Boolean algebra, which gate is expressed as (1) OR (2) NAND (3) AND (4) NOR p − n npn p pn npn iii ii i iii ii iv ii iv iii ii iii iv 10 eV eV 2 4 8 6 Y = ̄ ̄ ̄ ̄ ̄ ̄ ̄ ̄ ̄ ̄ ̄ ̄ ̄ ̄ ̄ A + B