Semiconductors Questions and Answers

23 Two particles are executing SHM on two parallel straight lines Amplitude A and time period T of both the particles are equal At time t particle is at displacement x A and other at 0 one A and they are approaching towards each X 2 other Time after which they will cross each other is 1 3 2 T 3 5T 6 4 T 6

171 The solids which have the negative temperature coefficient of resistance are metals insulators only semiconductors only insulators and semiconductors W 1 2 butt tember Sime 2

1 Consider two npn transistors as shown in figure If 0 Volts corresponds to false and 5 Volts correspond to true then the output at C corresponds to Online April 9 2013 cl sv SV ic 04 ov AO WWW BO WWW 2

1 elec An electric current i enters and leaves a uniform circular wire of radius a through diametrically opposite points A charged particle q moving along the axis of the circular wire passes through its centre at speed u The magnetic force acting on the particle when it passes through the centre has a magnitude qvoi 2a 1 qv 12 quo 2ra 3 qv Hoi a zero

The drift current in a p n junction is Question Type Single Correct Type 1 from the p side to the n side 2 from the n side to the p side if the junction is forward biased and in the opposi direction if it is reverse biased 3 from the n side to the p side A from the p side to the n side if the junction is forward biased and in the opposi

Zener breakdown in a semi conductor diode occurs when Question Type Single Correct Type 1 Forward current exceeds certain value 2 Reverse bias exceeds certain value 3 Forward bias exceeds certain lue 4 Potential barrier is reduced to zero

Imp A red LED emits light at 0 1 watt uniformly around it The amplitude of the electric field of the light at a distance of 1 m from the diode is a 5 48 V m c 1 73 V m b 7 75 V m d 2 45 V m

mp a 1 62 36 d 1 4 b 1 59 c 1 54 In a common base amplifier the phase difference betwe the input signal voltage and output voltage is d 0 a T b 4 c E N T 2

A diode is a device that allows current to be carried in only one direction the direction indicated by the arrowhead in its circuit symbol Find approximately in terms of AV and R the average power delivered to the diode circuit of the figure Assume that the diodes are ideal and AV is the rms voltage applied to the circuit R www Diode Diode R ww 2R R www

The output of microphone is rated at 52 db The reference level is 1 V under specified sound conditions What is output voltage of microphone under the same sound conditions 2 5 mV 3 8 mV 6 3 mV 1 5 mV 2500 uV

A multistage amplifier consists of three stages the voltage gain stages are 60 100 and 160 Calculate the overall gain in dB 11 964 10 dB 120 20 dB 12 020 10 dB 119 64 dB 1 1964 100 dB

23 The input signal given to a CE amplifier having a 1 voltage gain of 150 is V 2 cos 15t corresponding output signal will be 1 2 cos 15t 5 6 3 TC The I 1 3 300 cos 15t 2 2 300 cos 15t 4 3 4 75 cos 15t 2 3

27 In the following common emitter circuit if 100 VCE 7V VBE Negligible R 2 ko then I Ra ww B Rc E A 0 01 mA B 0 04 mA C 0 02 mA 15 V

In semiconductors at a room temperature A The valence band is partially empty and the conduction band is partially filled B The valence band is completely filled and the conduction band is partially filled C The valence band is completely filled D The conduction band is completely empty

A common emitter amplifier is designed with n p n transistor a 0 99 The input resistance is 1KQ and load is 10 KQ the voltage gain will be A 99 C 9 9 B 990 D 0 99

4 For the combination shown in figure which one of the given statements is wrong 1 A 0 and B 0 Y 0 2 A 0 and B 1 Y 0 A 3 A 1 and B 0 Y 1 4 A 1 and B 1 Y 0

In a photodiode the reverse current increases when exposed to light of wavelength of 750 nm or less The band gap of semiconductor used is O 1 2 eV O 1 65 eV O 0 9 eV O 1 50 eV

An electric bulb rated 100 W 100 V has to operated across 141 4 V 50 Hz A C supply Th capacitance of the capacitor which has to b connected in series with bulb so that bulb will glo with full intensity is NCERT Pg 25 10 3 1 F 2 4 10 2 1 F F

In case of an unbiased PN junction 1 N side is at higher potential than P side 2 N side is at lower potential than P side 3 There is no potential difference exists 4 No electric field is present

Determine the output f for the logic circuit shown below Minimize the output f function using Boolean algebra and sketch the minimized logic circuit D XO YO ZO Do Output

charge Q is of opposite polarity to that of q 8 When no current passes through a conductor choose which one of the following is incorrect 1 The average velocity of a free electrons over a large period of time is zero 2 The average of the velocities of all the free electrons at an instant is zero 3 The free electrons are randomly moving 4 The average speed of a free electron over a

Find the minimized solution for the following using Kmap F 0 1 4 5 9 11 14 15 Answer the following Number of octets and quads and pairs in the following K Map Answer like this octetquadpair 212 if there is 2 octets one quad two pair

In a common base mode of a transistor the collector current is 5 488 mA for an emitter current of 5 60 mA The value of the base current amplification factor B will be a 49 b 50

If in a p n junction a square input signal of IU V is applied as shown At 5 V A then the output across RL will be 5 V 5 V T 10 V RE

Teacher please explain isn t 1kohm our output resistance And if we find Vc across 1kohm then will it not be the ans wer Why we minus 18 Vc Please explain my concept Im ery confused 15 A common emitter amplifier is shown in the figure If 200 and VBE 0 5 V then value of Ic and VCE respectively will be NCERT Pg 499 5 V 90 kn www B 1 10 mA 10 V 1 kn C E 18 V 2 10 mA 8 V

18 The circuit diagram shows a logic combination 18 fer with the states of output X Y and Z given for inputs P Q R and S all at state 1 When inputs P and R change to state 0 with inputs Q and S still at 1 the states of outputs X Y and Z change to P 1 Q 1 R 1 1 1 0 0 3 0 1 0 X 1 Y 0 Z 0 2 1 1 1 4 0 0 1 afais gr sst useft ff P Q R S for at Fria X Y Para R 1 S 1 Z en ufafda da P 1 Q 1 1 1 0 0 3 0 1 0 ufafa EN 1 X 1 Y 0 X YAZ Z 0 2 1 1 1 4 0 0 1 Q

4 None of the above A piece of copper and other of germanium are cooled from room temperature to 100 K 1 Conductivity of copper increases and that of germanium decrease 2 Conductivity of copper decreases and that of germanium increases 3 Conductivity of copper as well as germanium both decreases 4 Conductivity of copper as well as germanium both increases

is taken across load resistance 6 ks if current In the given circuit Zener diode regulated voltage through 0 5 ks resistor is 4 mA then current in load resistor is V 10 V 1 2 67 mA 2 1 33 mA 0 5 k www 2 4 mA 4 2 mA 6 k

A p type semiconductor Is electrically positive Is electrically negative Is electrically neutral Is electrically positive for excessive doping

The energy band diagram of a semiconductor material is shown in figure C B V B The semiconductor is of n type E p type Intrinsic type Data is insufficient

A pure semiconductor crystal has 4 x 1027 atoms m It is doped by 4 ppm concentration of pentavalent atom The number of holes per m will be n 10 6 m 1011 m 3 10 m 3 101 m 3 108 m 3

In the following circuit of PN junction diodes D D2 and D3 are ideal then I is E R B E 2R C 2E 3R D E R www R ww R

5 In the following the diodes are either forward biased or reverse biased Choose the correct statement 8V9 www I A wwww 4V 6 8V 8V www II 8 Vo D III IV a I and II are forward biased and III and IV are reverse biased b I and IV are forward biased and II and III are reverse biased c I and III are forward biased and II and IV are reverse biased d II and III are forward biased and I and IV are reverse biased

s this in syllabus of NEET 2021 44 An amplifier A with a negative feedback is shown in the diagram Choose the correct expression for the close loop gain of the amplifier 1 A Amplifier A 1 AB Feedback ES TESundations 2 4 A 1 AB AB 1 AB Vo

The circuit as given in figure contains two diodes each with a forward resistance of 30 0 and with infinite backward resistance if the battery is 3 V the current through the 50 Q resistance in ampere is D D 3 V Zero 0001 0 02 7002 m 700 www 500

I V characteristics of solar cell lies in third quadrant of co ordinate axes y A B 14 The Boolean expression Y A B represents the 1 AND gate ZNA 3 OR gate NAND gate NOR gate frache ques A B

For a p n junction diode barrier potential Vo is shown for unbiased condition 321 Choose the correct statement among the following Both 2 and 3 represents forward biasing hr min Both 2 and 3 represents reverse biasing 2 represents forward biasing and 3 represents reverse biasing 3 represents reverse biasing and 1 represents forward biasing

Two logic circuits are shown in the figure A a BB The logic operation carried out by the two circuits are respectively A b NAND AND AND OR NAND NOR AND NOR X Y

The transfer characteristics between V and V for CE transistor is shown in the figure KL V The region in which transistor acts as a switch ON is Roth Land III

Single Correct MCQ The current voltage relation of diode is given V 1000 where the applied T I e by 1 mA voltage V is in volts and the temperature T is in kelvin If a student makes an error measuring 0 01 V while measuring the current of 5 mA at 300 K what will be the error in the value of current in mA A 0 5 mA B C 0 05 mA 0 2 mA

110 pn junction diodes are arranged as shown in the figures A and B Identify the bias applied to the diodes mA A 1 Both A and B show forward bias 2 Both A and B show reverse bias 3 A shows forward bias B shows reverse bias 4 A shows reverse bias B shows forward bias B

Pure Si at 500 K has equal number of electron n and hole n concentrations of 1 5 10 6 m Doping by indium increases n to 4 5 10 m The doped semiconductor is of h 1 p type having electron concentration n 5 x 10 m e 2 n type with electron concentration n 5 x 1022 m e 3 p type with electron concentration n 2 5 x 10 0 m e 4 n type with electron concentration 25 x 1023 m 3 n

What is the current through an ideal p n junction diode shown in figure below www 100 2 1 orrect Answer 3 Zero 10 mA 20 mA 50 mA 4 IV

What is A x B Is the and gate represented by the multip ly sign also As per we had read it s represented by A B or AB The output X of the logic circuit shown in figure will be A x Be AxB A B A B

a sv ww R b 10 V 12 V 1 2 c only 3 www Question Type Single Correct Type Q Game 5 V a and c a b and d b and d R 9 10 V are

diodes D D and D3 are ideal for the following potential of A and B The correct increasing order of resistance between A and B will be R 4 D D R Kww D i 10 V 5V ii 5V 10V ii 4V 12V R ww 1 i ii iii 3 ii iii R ww 2 iii ii i 56049 www CON R 4 B

electrons is 12 times to that of holes If number density of electrons is 3 times to the number density of holes then the ratio mobility of free electrons to holes is 1 2 3 2 3 1 3 4 1 4 4 3

1 To 1 1 3 Ao Bo ABY 000 1 0 0 0 1 1 ABY 000 01 1 1 0 1 1 1 1 Diode 1 K Diode 2 2 4 Q 5 V ABY 0 0 0 1 1 1 0 0 1 1 ABY 0 0 1 1 1 0 0 1 1 0

The small current in reverse bias condition are due to A B D Electrons Majority charge carriers i e electrons on n side and holes on p side Minority charge carriers i e electrons on p side and holes on n side Temperature

L Vgen i R M HE The circuit shown above has R 6 Ohms L 1 H and C 40 mF The capacitor has the initial voltage of Vc 0 4 00 volts and the switch is closed at t 0 The source voltage is Vgen 40t We want to write the IVP for this circuit Write the value of i 0