Semiconductors Questions and Answers

Q 15 The mobility of electrons in a semiconductor chip of length 10 cm is observed to be 1000 cm Vs When a potential difference of v is applied across it What is the drift speed of electrons Au 01 x nog 1 cm s 3 2000 m s rib 2 5 cm s 4 1000 m s es o

This is a subjective question hence you have to write your answer in the Text Field given below For the below CE amplifier find voltage gain input and output resistances Consider beta of the BJT is 65 Re 3302 www R 10 kQ Ra 100 k RE 16 kQ 943 HH Rout 145 220 k 6M

Q No 51 18 4 1 high speed steel contains ABCD A B C D vanadium 4 chromium 18 and tungsten 1 vanadium 1 chromium 4 and tungsten 18 vanadium 18 chromium 1 and tungsten 4 none of the above

6 A common emitter transistor amplifier is connected with a load resistance of 6 kQ When a small a c signal of 15 mV is added to the base emitter voltage the alternating base current is 20 A and the alternating collector current is 1 8 mA What is the voltage gain of the amplifier a 90 b 640 c 900 d 720

1 A transistor is connected in common emitter configuration The collector supply is 8 V and voltage drop across a resistor of 800 in collector circuit is 0 5 V If the current gain factor B 24 then base current will be 1 20 A 3 32 A 2 26 A 4 24 A

and the other O A gate in which all the inputs must be low to get a high output is called UPSEAT 2004 a A NAND gate c A NOR gate b An inverter d An AND gate Which logic gate is represented by the following

In case of LED if we increase forward applied voltage 1 Intensity of emitted light increases 2 Intensity of emitted light decreases 3 Intensity of emitted light first increases then decreases 4 Intensity of emitted light first decreases then increases Asked by 1230624 aesl id Standard XII Stream NEET Aug 1 2021 at 1 2 PI Add your responses Type Text Type your answer here OR you can upload an attachment from the option below

In the figure shown below chose the correct answer A B 502 C 20V Select an answer D D2 Voltage across D is 20 V Voltage across D is 20 V Current through diode D is 4 A

In an n p n transistor circuit the collector curren is 20 mA If 90 of emitted electron reach th collector 1 the emitter current will be 18 mA 2 emitter current will be 22 2 mA 3 base current will be 4 mA Amb0 0 Am 4 base current will be 2 mA

4 To T T 4 T T T 108 For a transistor I 25 mA and I 1 mA The value of 108 fr fay 25 m 1 current gain a will be 4327 24 8 4 GCI 1 4 24 Gurukripa Career Institute Pvt Ltd Jyoti Nagar Piprali Road Sikar Ph 01572 256688 21

of gates as shown for the given inputs A and B Be Do ABY 1 A A B 5 10 15 20 t H hldl Door Y 2 6 H

4 The voltage gain of a CE amplifier is 30 and input voltage 44 CE 30v sin60 is v sin600xt then output voltage will be at faria aceast 1 sin600zt 2 1 30sin600nt 3 30sin600 t 4 30cin600 t 1 sin600nt 2 1 30sin600nt 3 30sin600nt 4 30sin600 t

A triangular loop ABC carrying current 2 and an infinite wire carryin current are placed in the same plane If the magnetic force of interaction between the infinite wire and the loop ABC is in d towards left then find the value of n 2T 60 Correct answer 03

Which change particle does not exist in the depletion layer Options electron SMOCH hole FISI electron and hole None of these

The following configuration of gates is equivalent to A B Question Type Single Correct Type 1 NAND 2 OR Y

32 Identify the gate match A B Y in the bracket to check D 1 OR A 1 B1 Y 0 2 XOR A 0 B 0 Y 0 3 NOT A 1 B 1 Y 1 4 AND A 1 B 1 Y 1 32 A B Y fem faca i atzen a 1 OR A 1 B 1 Y 0 2 XOR A 0 B 0 Y 0 3 NOT A 1 B 1 Y 1 4 AND A 1 B 1 Y 1

9 The resistivity of alloy manganin is a Nearly independent of temperature b Increases rapidly with increase in temperature c Decreases with increase in temperature d Increases rapidly with decrease in temperature 10 A wire of length 1 and resistance R is stretched to get the radius of area of

For an n p n transistor doping concentration in Base region is N 1015 cm 3 doping concentration in collector region is No 1017 cm 3 The width of the Base region is 5 m 1 x 10 12 F cm and q 1 6 x 10 19C The minimum reverse biasing voltage Vcg required across the CB Junction to get the Breakdown Due to punch through is a 12 V c 20 V b 15 V d 25 V

Resistivity of N type germanium crystal is 62m Velocity of electron per unit electric field is 0 8 SI unit Number density of charge carrier is 1 1 3 x 10 m 3 5 2 x 10 m 2 2 6 x 10 m 4 7 8 x 10 m

6 A bar magnet of mass m is suspended from the ceiling with a massless string and is set into oscillations A gold metal plate is brought close to the oscillating pendulum The oscillations will damp due to induction of eddy currents in the metal Which one of the following statements is true if the gold plate is replaced by a steel plate having the same physical dimensions Of the two note that gold is a better conductor of electricity A the amplitude of oscillations will decrease faster B the amplitude of oscillations will decrease slower C the amplitude of oscillations will increase D the amplitude of oscillations will not be affected

1 In the circuit given the current through the battery is 15 V 1 20 mA 3 5 mA 500 1500 R V 10 V 2 6 67 mA 4 10 mA 41 f uffi 15 V 1 20 mA 31 5 mA R 500 1500 R V 10 V 2 6 67 mA 4 10 mA

4 A 1 B 1 C 1 4 The following figure i shows a logic gate circuit with two 4 inputs A and B and output C The voltage waveforms of A B and C are as shown in the figure ii given below B Logic gate circuit 0 11 B The logic circuit gate is 1 OR 2 AND 3 NAND 4 NOR 4 A 1 B 1 C 1 fa un acte fa a cui faut fada Agen Banff CIA Bff Logic gate circuit 1 1 OR 2 AND 3 NAND 4 NOR

The simplified block diagram of a 10 bit A D converter of dual slope integrator type is shown in figure The 10 bit counter at the output is clocked by a 1 MHZ clock Assuming negligible timing overhead for the control logic the maximum frequency of the analog signal that can be converted using this A D converter is approximately Input sampled to be converted Reference de innut Integrator Comparator and control Logic 10 bit Counter Digital Output

A bulb in a staircase has two switches one switch being at the ground floor and the other one at the first floor The bulb can be turned ON and also can be turned OFF by any one of the switches irrespective of the state of the other switch The logic of switching of the bulb resembles

Statement I We require the same no of XOR gates for binary to Gray conversion and vice versa Statement II Hence forth the same XOR gates can be used with a gating network and control circuit 1 Both are false 2 Only I is true m Both are true

In the given circuit the voltage across the load is maintaine at 12V The current in the zener diode varies from 0 50mA What is the maximum wattage of the diode 20V 1 12W 2 6W 3 0 6W 4 1 2W wwww

V is used for regulation The load current is to be 4 0 mA and the unregulated input is 10 0 V What should be the value of series resistor R Given zener current is 20 mA 10V O 6 0 V O O R ww 163 Q 167 Q 175 Q 186 Q ww Load

S A Zener diode is used in a voltage regulation circuit with series resistance R and load resistance R The maximum current that can pass through the Zener diode is I The maximum input voltage for which the Zener voltage V can be maintained at the output depends on the choice of Z A R R and I R and I only B Z C R and I only D I only 0 0 0

electrical cond Activity trinti Confers and Ictivity Umain pulchased explain b increases 4 First forthente Whey If a p n diode is reverse biased then the resistance measured by an ohm meter will be a high 4 c infinite b zero d low 1995

An ideal step graded p n junction has the following properties at the room temperature of 300K The doping concentration of the p region is 1024 m the doping concentration of the n region is 1022 m Assume the free electron and hole mobilities to be 0 05m V s and 0 14m V s respectively The intrinsic concentration of the semiconductor is 1 4 1016 m Calculate the conductivity of n region in mho m

Which of the given statements about transistor is not true a Emitter is heavily doped b Base is thin c Base is lightly doped d Collector region is smaller comparative to emitter in size 2014

A sinusoidal wave carrier voltage of frequency 2 MHz and amplitude 200 volts is amplitude modulated by the sinusoidal voltage of frequency 75 10 kHz producing modulation Calculate the frequency and amplitude of upper and lower sidebands A B C D 50 V 2010 kHz 1990 kHz 75 V 2010 kHz 1990 kHz 100 V 2015 kHz 1995 kHz 150 V 2020 kHz 1950 kHz

Pls explain I did not understand the language of question Pls explain the concept In the circuit diagram the input is across the terminal A and Cand the output is across Band D Then output is B A Zero Same as the input Full wave rectifier Half wave rectifier

8 Use this information to answer Question 8 9 A silicon pn junction step junction has doping densities of N 5 x 10 cm3 on the p side and N 1 x 10 cm on the n side Carrier lifetimes are given as T 10 s and Tp 10 s Assume long diode l e long quasi neutral regions Calculate the current density in A cm at a forward blas of V 0 5V Answers within 5 error will be considered correct

Some are saying that beacuse of single transitor it is a NO gate ut that switch explaination means it is AND gate Which o e is correct 17 A transistor with CE configuration can be realized as NCERT Pg 502 1 NOT gate 2 AND gate 3 OR gate NOR gate

For a voltage regulation circuit shown below the input voltage varies between 80 100 V The Zener voltage V is 50 V 80 100 VO 5 kQ wwww A 1 mA B 5 mA C 8mA D 16 mA V 50 V 10 kQ The minimum current through the Zener diode is

An npn transistor biased in active region as magnitude of collector base voltage is increase i Base current increases because more electrons are injected from the emitter ii Neutral width of base region increases ni Life of electrons in base region increases iv Base current decreases due to decrease in recombination rate v Collector current increases 1 i ii only correct 2 i ii iii are correct 3 iii frin or

The number of silicon atom per m is 5x1028 This is doped simultaneously with Arsenic and Indium at doping concentration 1 106 and 1 10 respectively Then number of hole is n 1 5 10 per m ne 1 4 95 1022 2 4 5 10 3 4 5 10 0 4 4 95 1020

A vertical straight conductor carries a current vertically upwards A point P lies to the east of it as a small distance and another point Q lies to the west at the same distance The magnetic field at P is A Greater than at Q B Same as at Q C Less than at Q R

i Avalance Breakdown occurs in a reverse bias of highly doped p n junction ii Zenner Breakdown occurs in lightly dopped p n junction iii The forward bias and reverse bias characteristics of p n junction do not obey ohm s law SolveLancer Test a Only i correct b ii iii both correct c Only iii correct

Directions for Qs 57 63 These questions consist of two statements each printed as Assertion and Reason While answering these questions you are required to choose any one of the following five responses a If both Assertion and Reason are correct and the Reason is a correct explanation of the Assertion b If both Assertion and Reason are correct but Reason is not a correct explanation of the Assertion If the Assertion is correct but Reason is incorrect If both the Assertion and Reason are incorrect If the Assertion is incorrect but the Reason is correct Assertion The resistivity of a semi conductor increases with temperature Reason The atoms of semi conductor vibrate with larger amplitude at higher temperatures thereby increasing its resistivity 2003 58 Assertion In a transition the base is made thin thin base makes the transistor stable c d e 57 1200

In the following common emitter configuration an npn transistor with current gain 100 is used The output voltage of the amplifier will be 2003 1mV 1kQ 10mV b 0 1V 10kQ T1 TO Vout c 1 0V d 10V of

Determine current through Sidiode for the electrical network shown in the figure Ge Ge Si 1 29 o KIKI KI MONK 10 V 0 3 0 3 0 t 1 1 93 A 3 3 1 2 4 5 2 2 9 A 6 A 3 302 I 10 uf

The width of the depletion layer of the pn junction is Answer A voltage independent of the applied B increased with the applied reverse voltage D C forward voltage increased with the applied increased with the doping

plotted for Answer A Ia anode current versus Ig gate current Va anode cathode voltage as a parameter B Ia versus Va with Ig as a parameter C Va versus Ig with Ia as a parameter C D Ig versus Vg with Ia as a parameter

8 The common emitter amplifier is shown in figure the input voltage applied is 10V and VBE 0 and VCE 4 V The value of current gain for the amplifier is 1 100 2 210 Vi w RB 500 kn 10 V j K Rc 2kQ2 2 150 50 CO RK NI

87 The Input signal given to CE amplifier having T a voltage gain of 100 is V 4 sin 100 nt The corresponding output signal will be T 1 400 sin 100 nt 5T 2 400 sin 100 nt 4 TU 3 0 04 sin 100 nt 4 3TT

mi grit 360 ko PAS ebolb ienes ei V of loupe eps riguo trenuo to epsllov nwobiseid ret S gonos 1 kQ 20 V Ama II 2 5 mA won beisluge1 pit ettini niw as 8 prived es beau Am 2 ai oboib ort aleboib The potential difference across base collecto Junction VCB is 1 1 V 2 13 V 3 4 V xa 8 es s s nl E VOS V ot t

In which of the following configuration both voltage gain and current gain are higher than unity 1 Common emitter configuration 2 Common base configuration 3 Both 1 and 2 4 None of the above

Vin applied 10 V and VBE 0 If VCE is 6 V then value of base current IB and collector current Ic are respectively 10 V 10 V 400 KQ 25 A 2 A 25 mA 2 mA O 25 A 2 mA O 25 mA 2 A 2 KQ