Feb 2023
Question 1. Choose the correct statement about Zener diode :
(a) It works as a voltage regulator in reverse bias and behaves like simple pn junction diode in forward bias.
(b) It works as a voltage regulator in both forward and reverse bias.
(c) It works as a voltage regulator only in forward bias.
(d) It works as a voltage regulator in forward bias and behaves like simple pn junction diode in reverse bias.
जीनर डायोड के लिए सही कथन चुनिए:
(a) पाश्चदिशिक वायस में यह वोल्टेज रेगुलेटर की तरह कार्य करता है एवं अग्रदिशिक वायस में साधारण p-n डायोड की तरह व्यवहार करता है। ।
(b) यह अग्रदिशिक एव पाश्चदिशिक वायस दोनों में वोल्टेज रेगुलटर की तरह कार्य करता है।
(c) यह केवल अग्रदिशिक वायस में वोल्टेज रेगुलेटर की तरह करता है।
(d) अग्रदिशिक बायस में यह वोल्टेज रेगुलेटर की तरह कार्य करता है एवं पाश्चदिशिक बायस में यह साधारण p - n डायोड की तरह व्यवहार करता है।
Answer (a)
Question 2. Match List I with List II:
Choose the correct answer from the options given below :
सूची I को सूची II से मिलाये
नीचे दिये गये विकल्पों से सही उत्तर चुनें :
(a) A-III, B-I, C-II, D-IV
(b) A-II, B-I, C-III, D-IV
(c) A-I, B-II, C-III, D-IV
(d) A-II, B-III, C-I, D-IV
Answer (d)
Jan-2023
Question 3. Given below are two statements :
Statement I: In a typical transistor, all three regions emitter, base and collector have same doping level.
Statement II: In a transistor, collector is the thickest and base is the thinnest segment.
In the light of the above statements, choose the most appropriate answer from the options given below.
नीचे दो कथन दिए गए हैं :
कथन I : किसी प्रारूप ट्रान्जिस्टर में, उत्सर्जक आधार एवं संग्राहक तीनों क्षेत्रों का अपामिश्रण (डोपिंग) स्तर समान होता है।
कथन II : एक ट्रान्जिस्टर में, संग्राहक सबसे चोडा एवं आधार सबसे पतला भाग होता है।
उपरोक्त कथनों के संदर्भ में, नीचे दिए गए विकल्पों में से सर्वाधिक उपयुक्त उत्तर चुनें :
(a) Statement I is correct but Statement II is incorrect
(b) Both Statement I and Statement II are incorrect
(c) Statement I is incorrect but Statement II is correct
(d) Both Statement I and Statement II are correct
Answer (c)
Question 4. The effect of increase in temperature on the number of electrons in conduction band `(n_e)` and resistance of a semiconductor will be as:
किसी अर्द्धचालक के प्रतिरोध एवं चालन बैंड (कंडक्शन बैंड) में इलेक्ट्रॉनों की संख्या `(n_e)` पर तापमान वृद्धि का प्रभाव निम्नवत होता है:
(a) `n_e` decreases, resistance increases
(b) Both `n_e` and resistance increase
(c) `n_e` increases, resistance decreases
(d) Both `n_e` and resistance decrease
Answer (c)
Question 5. The output `Y` for the inputs `A` and `B` of circuit is given by
परिपथ के निवेश `A` व `B` का निर्गत `Y` दिया गया है।
Truth table of the shown circuit is:
दिखाए गये परिपथ की सत्यता सारणी है:
(b)
(c)
(d)
Answer (a)
Question 6. The output waveform of the given logical circuit for the following inputs A and B as shown below, is :
दिए हुए लॉंजिक (तर्क) परिपथ में, निम्नलिखित इनपुट्स A एवं B के लिए प्राप्त निर्गत तरंग आरेख, नीचे प्रदर्शित है:
(b)
(d)
Answer (d)
Question 7. For the given logic gates combination, the correct truth table will be
दिए हुए तर्क (लॉजिक) गेट संयोजन के लिए, सही सत्यापन सारणी होगी :
(a)
(b)
(c)
(d)
Answer (d)
Question 8. Which one of the following statement is not correct in the case of light emitting diodes?
A. It is a heavily doped p-n junction.
B. It emits light only when it is forward biased.
C. It emits light only when it is reverse biased.
D. The energy of the light emitted is equal to or slightly less than the energy gap of the semiconductor used.
Choose the correct answer from the options given below:
(a) A
(b) B
(c) C & D
(d) C
Answer (d)
Question 9. Statement I : When a Si sample is doped with Boron, it becomes P type and when doped by Arsenic it becomes N-type semi conductor such that P-type has excess holes and N-type has excess electrons.
Statement II : When such P-type and N-type semi-conductors, are fused to make a junction, a current will automatically flow which can be detected with an externally connected ameter.
In the light of above statements, choose the most appropriate answer from the options given below
नीचे दो कथन दिए गए है।
कथन I: जब Si को बोरॉन द्वारा अपमिश्रित करने पर यह P-प्रकार अर्ध्द चालक बन जाता है और जब आर्सेनिक द्वारा अपमिश्रित करने पर N प्रकार के अर्ध्द चालक बन जाता है ताकि P प्रकार में कोटरों की और N प्रकार में इलैक्ट्रोनो की अधिकता हो जाती है।
कथन II : जब एक सन्धि बनाने के लिए इन P प्रकार व N प्रकार के अर्ध्द चालकों को छोडा जाता है तो स्वतःएक धारा बहने लगेगी जिस जुडे हुए बाह्य अमीटर द्वारा प्राप्त किया जाता है।
उपर्युक्त कथनों के संदर्भ में, नीचे दिए गए विकल्पों में से सर्वाधिक उपयुक्त उत्तर चुनिएँ :
(a) Statement I is incorrect but statement II is correct
(b) Both Statement I and statement II are correct
(c) Statement I is correct but statement II is incorrect
(d) Both Statement I and Statement II are incorrect
Answer (c)
Question 10. Given below are two statements : one is labelled as Assertion A and the other is labelled as Reason R
Assertion A : Photodiodes are used in forward bias usually for measuring the light intensity.
Reason R : For a p-n junction diode, at applied voltage V the current in the forward bias is more than the current in the reverse bias for `|V_z|>\pmV\geq|V_0|` where `v_0` is the threshold voltage and `V_z` is the breakdown voltage.
In the light of the above statements, choose the correct answer from the options given below
नीचे दो कथन दिए गए हैं : इनमें से एक को अभिकथन A एवं दूसरे को कारण R द्वारा निरूपित किया गया है ।
अभिकथन A: प्रकाश की तीव्रता का मापन करने के लिए, फोटोडायोड प्रायः अग्रदिशित बायसित अवस्था में प्रयुक्त होते हैं ।
कारण R: p-n संधि डायोड में आरोपित विभन V पर, `|V_z|>\pmV\geq|V_0|` के लिए,अग्रदिशित बायस में धारा का मान, पश्चदिशिक बायस में धारा के मान से अधिक होता है। जहां `V_z` भंजन वोल्टता है और `V_0` देहली वोल्टता है।
उपरोक्त कथनों के आधार पर, नीचे दिए गए विकल्पों में से सही उत्तर चुनें ।
(a) Both A and R are true but R is NOT the correct explanation of A
(b) A is true but R is false
(c) Both A and R are true and R is the correct explanation of A
(d) A is false but R is true
Answer (d)
Question 11.
The logic gate equivalent to the given circuit diagram is :
दिया गया परिपथ चित्र लॉजिक गेट के समतुल्य है :
(a) NOR
(b) OR
(c) NAND
(d) AND
Answer (C)
Question 12. Given below are two statements : one is labelled as Assertion A and the other is labelled as Reason R
Assertion A : Photodiodes are preferably operated in reverse bias condition for light intensity measurement.
Reason R : The current in the forward bias is more than the current in the reverse bias for a `p-n` junction diode.
In the light of the above statements, choose the correct answer from the options given below :
नीचे दो कथन दिये गये हैं : एक को अभिकथन A कहा गया है तथा दूसरे को कारण R कहा गया है
अभिकथन A: प्रकाश की तीव्रता मापने के लिए फोटो डायडों को उत्क्रम अभिनत (रिवर्स वाइअस) अवस्था में अधिक प्रयोग किया जाता है।
कारण R: `p-n` सन्धि डायोड के लिए अग्र अभिनत में धारा इसकी उत्क्रम अभिनत में धारा से अधिक होती है।
उपरोक्त कथनों के आधार पर, नीचे दिये गये विकल्पों में से सही उत्तर चुनिए:
(a) Both A and R are true and R is the correct explanation of A
(b) A is false but R is true
(c) A is true R is false
(d) Both A and R are true but R is NOT the correct explanation of A
Answer (d)
July-2022
Question 13. Choose the correct statement about Zener diode :
(a) It works as a voltage regulator in reverse bias and behaves like simple pn junction diode in forward bias.
(b) It works as a voltage regulator in both forward and reverse bias.
(c) It works as a voltage regulator only in forward bias.
(d) It works as a voltage regulator in forward bias and behaves like simple pn junction diode in reverse bias.
जेनर डायोड के बारे में सही कथन चुनें:
(a) यह रिवर्स बायस में वोल्टेज रेगुलेटर के रूप में काम करता है और फॉरवर्ड बायस में साधारण pn जंक्शन डायोड की तरह व्यवहार करता है।
(b) यह फॉरवर्ड और रिवर्स बायस दोनों में वोल्टेज रेगुलेटर के रूप में काम करता है।
(c) यह केवल फॉरवर्ड बायस में वोल्टेज रेगुलेटर के रूप में काम करता है।
(d) यह फॉरवर्ड बायस में वोल्टेज रेगुलेटर के रूप में काम करता है और रिवर्स बायस में साधारण pn जंक्शन डायोड की तरह व्यवहार करता है।
Answer (a)
Quesion 14. An n.p.n transistor with current gain `\beta=100` in common emitter configuration is shown in figure. The output voltage of the amplifier will be
चित्र में दर्शाये अनुसार, उभयनिष्ट - उत्सर्जक अभिविन्यास में लगे किसी `n-p-n` ट्रान्जिस्टर की धारा लब्धि `\beta=100` है। प्रवर्धक का निर्गत (आउटपुट) वोल्टेज होगा
(b) `1.0V`
(c) `10V`
(d) `100V`
Answer (b)
Question 15. Identify the solar cell characteristics from the following options :
सोलर सैल के अभिलक्षण निम्न में से किस चित्र में प्रदर्शित हैं ?
(a)
(b)
(c)
(d)
Answer (b)
Question 15. For a constant collector-emitter voltage of `8V`, the collector current of a transistor reached to the value of `6mA` from `4mA`, whereas base current changed from `20\muA` to `25\muA` value. If transistor is in active state, small signal current gain (current amplification factor) will be :
`8V` स्थिर मान वाले संग्राहक-उत्सर्जक वोल्टेज के लिए, किसी ट्रान्जिस्टर की धारा का मान `4mA`
से `6mA` पर पहुँचता है, जबकि आधार धारा का मान `20\muA` से `25\muA` के मान पर परिवर्तित होता है। यदि ट्रान्जिस्टर सक्रिय अवस्था में है, तो लघु सिग्नल धारा लब्धि ( धारा प्रवर्धक गुणांक) का मान होगा :
(a) `240`
(b) `400`
(c) `0.0025`
(d) `200`
Answer (b)
Question 16. A logic gate circuit has two inputs `A` and `B` and output `Y`. The voltage waveforms of `A`, `B` and `Y` are shown below.
The logic gate circuit is :
किसी लॉजिक गेट परिपथ में दो निवेश (इनपुट) A एवं B हैं तथा निर्गत (आउटपुट) Y है । A,B एवं Y
के वोल्टेज वक्र आरेख नीचे प्रदार्शित हैं ।
लॉजिक गेट परिपथ होगा:
(a) AND gateलॉजिक गेट परिपथ होगा:
(b) OR gate
(c) NOR gate
(d) NAND gate
Answer (a)
Question 17. In the circuit, the logical value of `A=1` or `B=1` when potential at A or B is `5V` and the logical value of `A=0` or `B=0` when potential at `A` or `B` is `0V`. The truth table of the given circuit will be :
परिपथ में, A या B, `5V` के विभव पर हैं तो तार्किक मान `A=1` या `B=1` हैं। तथा A या B `0V` पर हैं तो तार्किक मान `A=0` या `B=0` हैं दिए गए परिपथ की सत्यापन सारणी होगी :
(a) A B Y
0 0 0
1 0 0
0 1 0
1 1 1
(b) A B Y
0 0 0
1 0 1
0 1 1
1 1 1
(c) A B Y
0 0 0
1 0 0
0 1 0
1 1 0
(d) A B Y
0 0 1
1 0 1
0 1 1
1 1 0
Answer (a)
Jun-2022
Question 18. In the given circuit the input voltage Vin is shown in figure. The cut-in voltage of `p-n` junction diode `(D_1 or D_2)` is `0.6 V`. Which of the following output voltage `(V_0)` waveform across the diode is correct?
(a) `\alpha={1-\beta}/{\beta}`
(b) `\beta={\alpha}/{1-\alpha}`
(c) `\alpha\beta=1`
(d) `\alpha={\beta}/{1-\beta}`
Answer (b)
Question 33. For a transistor in CE mode to be used as an amplifier, it must be operated in :
(a) Both cut-off and Saturation
(b) Saturation region only
(c) Cut-off region only
(d) The active region only
Answer (d)
Question 34. Four NOR gates are connected as shown in figure. The truth table for the given figure is :
(a)
(b)
(c)
(d)
Answer (d)
(a) A B Y
0 0 0
1 0 0
0 1 0
1 1 1
(b) A B Y
0 0 0
1 0 1
0 1 1
1 1 1
(c) A B Y
0 0 0
1 0 0
0 1 0
1 1 0
(d) A B Y
0 0 1
1 0 1
0 1 1
1 1 0
Answer (a)
Jun-2022
Question 18. In the given circuit the input voltage Vin is shown in figure. The cut-in voltage of `p-n` junction diode `(D_1 or D_2)` is `0.6 V`. Which of the following output voltage `(V_0)` waveform across the diode is correct?
दिए हुए परिपथ का निवेश (इनपुट) वोल्टेज (विभव) Vin चित्र में प्रदर्शित है। `p-n` संधि डायोड
`(D_1` या `D_2)` का अंतक वोल्टेज `0.6V` है। डायोड के सिरों पर प्राप्त निर्गत (आउटपुट) वोल्टेज `(V_0)` के लिए कौन सा वक्र सही है ?
(a)
(b)
(c)
(d)
Answer (d)
Question 19. In the following circuit, the correct relation between output (Y) and inputs A and B will be :
(a) `Y=AB`
(b) `Y=A+B`
(c) `Y=\bar{AB}`
(d) `Y=\bar{A+B}`
Answer (c)
Question 20. For using a multimeter to identify diode from electrical components, choose the correct statement out of the following about the diode :
Answer (b)
Question 21. Given below are two statements : One is labelled as Assertion A and the other is labelled as Reason R.
(a) Both A and R are true and R is correct explanation of A
(b) Both A and R are true but R is NOT the correct explanation of A
(c) A is true but R is false
(d) A is fslse but R is true
Answer (a)
Question 22. For a transistor to act as a switch, it must be operated in
(a) Active region
(b) Saturation state only
(c) Cut-off state only
(d) Saturation abd cut-0ff state
Answer (d)
Question 23. Identify the correct Logic Gate for the following output (Y) of two inputs A and B.
(a)
(b)
(c)
(d)
Answer (b)
Question 24. The positive feedback is required by an amplifier to act an oscillator. The feedback here means :
Answer (b)
Question 25. The `I-V` characteristics of a `p-n` junction diode in forward bias is shown in the figure. The ratio of dynamic resistance, corresponding to forward bias voltage of `2 V` and `4 V` respectively, is :
(a) `1:2`
(b) `5:1`
(c) `1:40`
(d) `20:1`
Answer (b)
Question 26. Identify the logic operation performed by the given circuit:
(a) AND gate
(b) OR gate
(c) NOR gate
(d) NAND gate
Answer (a)
Question 27. The photodiode is used to detect the optical signals. These diodes are preferably operated in reverse biased mode because :
Answer (d)
Sep-2021
Question 28. In the given figure, each diode has a forward bias resistance of `30\Omega` and infinite resistance in reverse bias. The current `I_1` will be :
(a) `3.75A`
(b) `2.35A`
(c) `2A`
(d) `2.73A`
Answer (c)
Aug-2021
Question 29. If `V_A` and `V_B` are the input voltages (either `5_V` or `0_V`) and `V_0` is the output voltage then the two gates represented in the following circuit (A) and (B) are :-
(a)
(b)
(c)
(d)
Answer (d)
Question 19. In the following circuit, the correct relation between output (Y) and inputs A and B will be :
नीचे दिए गए परिपथ में, आउटपुट (Y) एवं इनपुट (A तथा B) के बीच सही सम्बंध होगा :
(a) `Y=AB`
(b) `Y=A+B`
(c) `Y=\bar{AB}`
(d) `Y=\bar{A+B}`
Answer (c)
Question 20. For using a multimeter to identify diode from electrical components, choose the correct statement out of the following about the diode :
(a) It is two terminal device which conducts current in both directions.
(b) It is two terminal device which conducts current in one direction only.
(c) It does not conduct current gives an initial deflection which decays to zero.
(d) It is three terminal device which conducts current in one direction only between central terminal and either of the remaining two terminals
विद्युत अवयवों में से डायोड की पद्धचान करने के लिए प्रयुक्त एक मल्टीमीटर के लिए, निम्न में से सद्धी कथन चुनिए:
(a) यह दो सिरों वाला यंत्र है, जिसमें दोनों दिशाओं में धारा प्रवाहित होती है।
(b) यह दो सिरों वाला यंत्र है, जिसमें धारा एक दिशा में प्रवाहित होती है।
(c) इसमें धारा प्रवाहित नहीं होती, एक प्रारमिभक विक्षेप आता है जो कि शून्य की तरफ घटता जाता है।
(d) यह तीन सिरों वाला यंत्र है, जिसमें मध्य वाले सिरे एवं बाकी दोनों में से किसी एक सिरे के बीच, एक ही दिशा में धारा प्रवाहित होती है।
Answer (b)
Question 21. Given below are two statements : One is labelled as Assertion A and the other is labelled as Reason R.
Assertion A : n-p-n transistor permits more current than a p-n-p transistor.
Reason R : Electrons have greater mobility as a charge carrier.
Choose the correct answer from the options given below :
(a) Both A and R are true and R is correct explanation of A
(b) Both A and R are true but R is NOT the correct explanation of A
(c) A is true but R is false
(d) A is fslse but R is true
Answer (a)
Question 22. For a transistor to act as a switch, it must be operated in
(a) Active region
(b) Saturation state only
(c) Cut-off state only
(d) Saturation abd cut-0ff state
Answer (d)
Question 23. Identify the correct Logic Gate for the following output (Y) of two inputs A and B.
(a)
(b)
(c)
(d)
Answer (b)
(a) External input is necessary to sustain ac signal in output.
(b) A portion of the output power is returned back to the input.
(c) Feedback can be achieved by LR network.
(d) The base-collector junction must be forward biased.
Answer (b)
Question 25. The `I-V` characteristics of a `p-n` junction diode in forward bias is shown in the figure. The ratio of dynamic resistance, corresponding to forward bias voltage of `2 V` and `4 V` respectively, is :
(a) `1:2`
(b) `5:1`
(c) `1:40`
(d) `20:1`
Answer (b)
Question 26. Identify the logic operation performed by the given circuit:
(a) AND gate
(b) OR gate
(c) NOR gate
(d) NAND gate
Answer (a)
Question 27. The photodiode is used to detect the optical signals. These diodes are preferably operated in reverse biased mode because :
(a) fractional change in majority carriers produce higher forward bias current
(b) fractional change in majority carriers produce higher reverse bias current
(c) fractional change in minority carriers produce higher forward bias current
(d) fractional change in minority carriers produce higher reverse bias current
Answer (d)
Sep-2021
Question 28. In the given figure, each diode has a forward bias resistance of `30\Omega` and infinite resistance in reverse bias. The current `I_1` will be :
(a) `3.75A`
(b) `2.35A`
(c) `2A`
(d) `2.73A`
Answer (c)
Aug-2021
Question 29. If `V_A` and `V_B` are the input voltages (either `5_V` or `0_V`) and `V_0` is the output voltage then the two gates represented in the following circuit (A) and (B) are :-
(a) AND and OR gate
(b) OR and NOT gate
(c) NAND and NOR gatr
(d) AND and NOT gate
Answer (b)
Question 30. In the following logic circuit the sequence of the inputs A, B are `(0, 0), (0, 1), (1, 0)` and `(1, 1)`. The output Y for this sequence will be :
(a) `1, 0, 1, 0`
(b) `0,1,0,1`
(c) `1,1,1,0`
(d) `0,0,1,1`
Answer (c)
Question 31. Choose the correct waveform that can represent the voltage across R of the following circuit, assuming the diode is ideal one :
(a)
(b)
(c)
(d)
Answer (d)
Question 32. For a transistor `\alpha` and `\beta` are given as `\alpha={I_C}/{I_E}` and `\beta={I_C}/{I_B}`. Then the correct relation between `\alpha` and `\beta` will be :
(b) OR and NOT gate
(c) NAND and NOR gatr
(d) AND and NOT gate
Answer (b)
Question 30. In the following logic circuit the sequence of the inputs A, B are `(0, 0), (0, 1), (1, 0)` and `(1, 1)`. The output Y for this sequence will be :
(a) `1, 0, 1, 0`
(b) `0,1,0,1`
(c) `1,1,1,0`
(d) `0,0,1,1`
Answer (c)
Question 31. Choose the correct waveform that can represent the voltage across R of the following circuit, assuming the diode is ideal one :
(a)
(b)
(c)
(d)
Answer (d)
Question 32. For a transistor `\alpha` and `\beta` are given as `\alpha={I_C}/{I_E}` and `\beta={I_C}/{I_B}`. Then the correct relation between `\alpha` and `\beta` will be :
(a) `\alpha={1-\beta}/{\beta}`
(b) `\beta={\alpha}/{1-\alpha}`
(c) `\alpha\beta=1`
(d) `\alpha={\beta}/{1-\beta}`
Answer (b)
Question 33. For a transistor in CE mode to be used as an amplifier, it must be operated in :
(a) Both cut-off and Saturation
(b) Saturation region only
(c) Cut-off region only
(d) The active region only
Answer (d)
Question 34. Four NOR gates are connected as shown in figure. The truth table for the given figure is :
(a)
(b)
(c)
(d)
Answer (d)
Question 35. Identify the logic operation carried out by the given circuit :-
(a) OR
(b) AND
(c) NOR
(d) NAND
Answer (c)
Question 36. 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 :
(a) Statement - I is true but Statement - II is false.
(b) Statement - I is false but Statement - II is true.
(c) Both Statement I and Statement II are true.
(d) Both Statement I and Statement II are false.
Answer (a)
Question 37. Find the truth table for the function Y of A and B represented in the following figure.
(a)
(b)
(c)
(d)
Answer (b)
Question 38. Identify the logic operation carried out.
(a) OR
(b) AND
(c) NOR
(d) NAND
Answer (b)
Question 39.Consider a situation in which reserve biased current of a particular `P-N` junction increases when it is exposed to a light of wavelength `\leq621 nm`. During this process, enhancement in carrier concentration takes place due to generation of hole-electron pairs. The value of band gap is nearly.
(a) `1eV`
(b) `4eV`
(c) `0.5eV`
(d) `2eV`
Answer (d)
Question 40. For the circuit shown below, calculate the value of `I_z` :
(a) `25mA`
(b) `0.1A`
(c) `0.15A`
(d) `0.05A`
Answer (A)
Mar-2021
Question 41. The correct relation between `\alpha` (ratio of collector current to emitter current) and `\beta` (ratio of collector current to base current) of a transistor is :
(a) `\beta={\alpha}/{1+\alpha}`
(b) `\alpha={\beta}/{1-\alpha}`
(c) `\alpha={\beta}/{1+\alpha}`
(d) `\alpha={1}/{1-\alpha}`
Answer (c)
Question 42. Which one of the following will be the output of the given circuit?
(a) XOR gate
(b) NOR gate
(c) NAND gate
(d) AND gate
Answer (a)
Question 43. The output of the given combination gates represents :
(a) AND gate
(b) NOR gate
(c) NAND gate
(d) XOR gate
Answer (c)
Question 44. The following logic gate is equivalent to :
(a) NOR Gate
(b) NAND Gate
(c) OR Gate
(d) AND Gate
Answer (a)
Question 45. Draw the output signal Y in the given combination of gates.
(a)
(b)
(c)
(d)
Answer (a)
Question 46. LED is constructed from Ga-As-P semiconducting material. The energy gap of this LED is `1.9 eV`. Calculate the wavelength of light emitted and its colour.
`[h=6.63\times10^{-34}Js, & C=3\times10^8 ms^-1 ]`
(a) `654 nm ` and orange colour
(b) `654 nm ` and red colour
(c) `1046 nm` and red colour
(d) `1046 nm` and blue colour
Answer (b)
Question 47. For extrinsic semiconductors; when doping level is increased;
(b) Fermi-level of p-type semiconductor will go upward and Fermi-level of n-type semiconductors will go downward
(c) Fermi-level of p and n-type semiconductors will not be affected.
(d) Fermi-level of p-type semiconductors will go downward and Fermi- level of n-type semiconductor will go upward.
Answer (d)
Question 48. The truth table for the following logic circuit is :
(a)
(a)
(b)
(c)
(d)
Answer (a)
Question 46. LED is constructed from Ga-As-P semiconducting material. The energy gap of this LED is `1.9 eV`. Calculate the wavelength of light emitted and its colour.
`[h=6.63\times10^{-34}Js, & C=3\times10^8 ms^-1 ]`
(a) `654 nm ` and orange colour
(b) `654 nm ` and red colour
(c) `1046 nm` and red colour
(d) `1046 nm` and blue colour
Answer (b)
Question 47. For extrinsic semiconductors; when doping level is increased;
(a) Fermi-level of both p-type and n-type semiconductors will go upward for T > `T_F`K and downward for T < `T_F`K, where `T_F` is Fermi temperature.
(b) Fermi-level of p-type semiconductor will go upward and Fermi-level of n-type semiconductors will go downward
(c) Fermi-level of p and n-type semiconductors will not be affected.
(d) Fermi-level of p-type semiconductors will go downward and Fermi- level of n-type semiconductor will go upward.
Answer (d)
Question 48. The truth table for the following logic circuit is :
(a)
(b)
(c)
(d)
Answer (d)
Question 49. A 5V battery is connected across the points X and Y. Assume `D_1` and `D_2` to be normal silicon diodes. Find the current supplied by the battery if the `+ve` terminal of the battery is connected to point X.
(a) `\sim 0.5A`
(b) `\sim 1.5A`
(c) `\sim 0.43A`
(d) `\sim 0.86A`
Answer (c)
Question 50. Given below are two statements :
Statement I : PN junction diodes can be used to function as transistor, simply by connecting two diodes, back to back, which acts as the base terminal.
Statement II : In the study of transistor, the amplification factor `\beta` indicates ratio of the collector current to the base current.
In the light of the above statements, choose the correct answer from the options given below.
(a) Both Statement I and Statement II are false
(b) Statement I is false but Statement II is true
(c) Both Statement I and Statement II are true
(d) Statement I is true but Statement II is false
Answer (b)
Question 51. Zener breakdown occurs in a `p-n` junction having p and n both :
(a) heavily doped and have wide depletion layer.
(b) lightly doped and have narrow depletion layer.
(c) heavily doped and have narrow depletion layer.
(d) lightly doped and have wide depletion layer.
Question 52. If an emitter current is changed by 4 mA, the collector current changes by `3.5 mA`. The value of `\beta` will be :
(a) `0.875`
(b) `0.5`
(c) `3.5`
(d) `7`
Answer (d)
Sep-2020
Question 53. With increasing biasing voltage of a photodiode, the photocurrent magnitude:
(a) Increases initially and after attaining certain value, it decreases
(b) Increases linearly
(c) Increases initially and saturates finally
(d) Remains constant
Question 54. Identify the operation performed by the circuit given below :
(a) AND
(b) NAND
(c) OR
(d) NOT
Answer (a)
Question 55. If a semiconductor photodiode can detect a photon with a maximum wavelength of `400 nm`, then its band gap energy is :
`[h=6.63\times10^-34 Js, C=3\times10^8 ms^-1]`
(a) `1.5eV`
(b) `2.0eV`
(c) `3.1eV`
(d) `1.1eV`
Answer (c)
(a) Multimeter shows NO deflection in both cases i.e. before and after reversing the probes if the chosen component is metal wire. A
(b) Multimeter shows a deflection, accompanied by a splash of light out of connected component in one direction and NO deflection on reversing the probes if the chosen component is LED. B
(c) Multimeter shows an equal deflection in both cases i.e. before and after reversing the probes if the chosen component is resistor.
(d) Multimeter shows NO deflection in both cases i.e. before and after reversing the probes if the chosen component is capacitor.
Answer (d)
Question 57. When a diode is forward biased, it has a voltage drop of `0.5 V`. The safe limit of current through the diode is `10 mA`. If a battery of emf `1.5 V` is used in the circuit, the value of minimum resistance to be connected in series with the diode so that the current does not exceed the safe limit is
(a) `50\Omega`
(b) `200\Omega`
(c) `300\Omega`
(d) `100\Omega`
Answer (d)
Question 58. In the following digital circuit, what will be the output at ‘Z’, when the
input (A, B) are `(1, 0), (0, 0), (1, 1,), (0, 1)`
(a) `1,1,0,1`
(b) `0,1,0,0`
(c) `1,0,1,1`
(d) `0,0,1,0`
Answer (d)
Jan-2020
(a) `1,1,0,1`
(b) `0,1,0,0`
(c) `1,0,1,1`
(d) `0,0,1,0`
Answer (d)
Jan-2020
Question 59. Two identical capacitors A and B, charged to the same potential `5V` are connected in two different circuits as shown below at time `t = 0`. If the charge on capacitors A and B at time `t = CR` is `Q_A` and `Q_B` respectively, then (Here e is the base of natural logarithm)
(a) `Q_A={CV}/e , Q_B={VC}/2`
(b) `Q_A={CV}/2 , Q_B={VC}/e`
(c) `Q_A=VC , Q_B={VC}/e`
(d) `Q_A=VC , Q_B=CV`
Answer (c)
Question 60. In the given circuit, value of Y is :
(a) toggles between 0 and 1
(b) 1
(c) will not execute
(d) 0
Answer (d)
Question 61. Boolean relation at the output stage-Y for the following circuit is :
(a) `A.B`
(b) `\bar{A}+\bar{B}`
(c) `\bar{A}.\bar{B}`
(d) `A+B`
Answer (c)
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