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Chapter 19

Electronic Devices - all with Video Answers

Educators


Chapter Questions

00:56

Problem 2560

C, Si and Ge have same no. of valence electrons. $C$ is an insulator because energy required to take one electron out from
(A) Si is more
(B) $\mathrm{C}$ is more
(C) Ge is more
(D) $\mathrm{C}$ is less

Akash Goyal
Akash Goyal
Numerade Educator
01:29

Problem 2561

Ionization energy of isolated phosphorous atom $10 \mathrm{eV}$. Ionization energy of same atom in Si is nearly $\mathrm{eV}$
(Relative Permittivity of silicon $=12$ )
(A) $0.1$
(B) $0.2$
(C) $0.3$
(D) $0.4$

Prem Bijarniya
Prem Bijarniya
Numerade Educator
01:15

Problem 2562

By adding impurity in intrinsic semiconductor $\mathrm{P}$ type semiconductor is made. charge of these P type semiconductor is
(A) trivalent, neutral
(B) pentavalent, neutral
(C) pentavalent, positive
(D) trivalent, negative

Varsha Aggarwal
Varsha Aggarwal
Numerade Educator
01:23

Problem 2563

Strong overlapping of different atomic orbital's makes
(A) different energy level
(B) energy band
(C) Conductor
(D) Insulators

AK
Ankur Khosla
Numerade Educator
01:41

Problem 2564

We can not make $\mathrm{p}-\mathrm{n}$ junction diode by making $\mathrm{P}$ type semi-conductor join with N-type semi-conductor, because
(A) Inter-atomic spacing becomes less than $1 \mathrm{~A}^{\circ}$
(B) P-type will repel N-type
(C) There will be discontinuity for the flowing charge carriers
(D) semi-conducting properties will be lost

Aman Kumar
Aman Kumar
Numerade Educator
02:19

Problem 2565

For $\mathrm{p}-\mathrm{n}$ junction, which statement is incorrect
(A) Donor atoms are depleted of their holes in junction
(B) No net charge exists far from junction
(C) Barrier potential $\mathrm{V}_{\mathrm{B}}$ is generated
(D) Energy $\mathrm{V}_{\mathrm{B}}$ is to be surmounted before any charge can flow across junction

Mahipal Kumawat
Mahipal Kumawat
Numerade Educator
02:38

Problem 2566

The intrinsic semi-conductor has :
(A) a finite resistance which does not change with temperature
(B) infinite resistance which decreases with temperature
(C) Finite resistance which decreases with temperature
(D) Finite resistance which does not change with temperature

Aman Kumar
Aman Kumar
Numerade Educator
01:01

Problem 2567

The behavior of Ge as semi-conductor is due to width of:
(A) Conduction band being large
(B) Forbidden band being large
(C) Conduction band being small
(D) Forbidden band being small and narrow

Narayan Hari
Narayan Hari
Numerade Educator
01:16

Problem 2568

Which of the following is not the advantage of PN junction diode over tube valve?
(A) Unlimited life
(B) No warming-up time after switching
(C) Large efficiency
(D) Low consumption of Power

Ajay Singhal
Ajay Singhal
Numerade Educator
02:38

Problem 2569

The forward biased diode is

Aman Kumar
Aman Kumar
Numerade Educator
01:04

Problem 2570

The truth table for gate is:
The gate is:
(A) $\mathrm{OR}$
(B) NOR
(C) NAND
(D) AND

Anand Jangid
Anand Jangid
Numerade Educator
02:01

Problem 2571

A current gain for a transistor working as CB amplifier is $0.90$. If emitter current is $10 \mathrm{~mA}$, then base current is
(A) $1 \mathrm{~m} \mathrm{~A}$
(B) $2 \mathrm{~m} \mathrm{~A}$
(C) $0.1 \mathrm{~mA}$
(D) $0.2 \mathrm{~mA}$

Aman Kumar
Aman Kumar
Numerade Educator
01:18

Problem 2572

For a transistor $\left(\mathrm{I}_{\mathrm{C}} / \mathrm{I}_{\mathrm{E}}\right)=0.96$, then $\mathrm{CE}$ current gain is:
(A) 12
(B) 6
(C) 24
(D) 48

Ajay Singhal
Ajay Singhal
Numerade Educator
01:04

Problem 2573

The given truth table is for which logic gate?
(A) $\mathrm{XOR}$
(B) AND
(C) NAND
(D) NOR

Anand Jangid
Anand Jangid
Numerade Educator
01:48

Problem 2574

For the given circuit of ideal P.N junction diode which is correct?
(A) In F.B, the voltage across $R$ is $\mathrm{V}$
(B) In R.B, the voltage across $\mathrm{R}$ is $\mathrm{V}$
(C) In $\mathrm{F} \cdot \mathrm{B}$, the voltage across $\mathrm{R}$ is $-\mathrm{V}$
(D) In R.B the voltage across $R$ is $-\mathrm{V}$

Ajay Singhal
Ajay Singhal
Numerade Educator
01:30

Problem 2575

At $0^{\circ} \mathrm{K}$ temp, a N-type semi-conductor:
(A) does not have any charge carriers
(B) has few holes but no free electrons
(C) few holes and few electrons
(D) has equal number of holes and electrons

Christina Sorrentino
Christina Sorrentino
Numerade Educator
01:10

Problem 2576

In Si-crystal, impurity donor atom have valency.
(A) 2
(B) 3
(C) 4
(D) 5

Akash Goyal
Akash Goyal
Numerade Educator
02:23

Problem 2577

A N-P-N transistor conducts when collector is and emitter is with respect to base.
(A) positive, negative
(B) positive, positive
(C) negative, negative
(D) negative, positive

Aman Kumar
Aman Kumar
Numerade Educator
01:46

Problem 2578

A full wave rectifier is operating at $50 \mathrm{~Hz}, 220 \mathrm{~V}$ the fundamental frequency of ripple will be
(A) $50 \mathrm{~Hz}$
(B) $75 \mathrm{~Hz}$
(C) $110 \mathrm{~Hz}$
(D) $100 \mathrm{~Hz}$

Aman Kumar
Aman Kumar
Numerade Educator
01:35

Problem 2579

Reverse bias applied on a junction diode:
(A) raises the potential barrier
(B) increases majority charge carrier current
(C) lowers the potential barrier
(D) increases the temperature of junction

Ajay Singhal
Ajay Singhal
Numerade Educator
01:09

Problem 2580

In the figure, the input is across $\mathrm{A}$ and $\mathrm{C}$ and output is across $\mathrm{B}$ and $\mathrm{D}$. The output is
(A) same as input
(B) Half wave rectified
(C) Full wave rectified
(D) zero

Varsha Aggarwal
Varsha Aggarwal
Numerade Educator
01:09

Problem 2581

In the figure, the input is across $B$ and $D$ and output is across $\mathrm{A}$ and $\mathrm{C}$. The output is
(A) same as input
(B) Half wave rectified
(C) Full wave rectified
(D) zero

Varsha Aggarwal
Varsha Aggarwal
Numerade Educator
01:33

Problem 2582

Digital circuits can be made to be respective use of:
(A) AND gate
(B) OR gate
(C) NOT gate
(D) NAND gate

Manik Pulyani
Manik Pulyani
Numerade Educator
01:15

Problem 2583

The output current versus time curve of a rectifier is shown in the figure. The average value of the output-current is
(A) 0
(B) $\left(\mathrm{I}_{0} / 2\right)$
(C) $\left(2 \mathrm{I}_{0} / \pi\right)$
(D) I $_{0}$

Varsha Aggarwal
Varsha Aggarwal
Numerade Educator
01:03

Problem 2584

A sinusoidal voltage of peak value 200 volts is connected to a diode and resistor $\mathrm{R}$ in the circuit shown. If diode is ideal, the r.m.s. voltage across $\mathrm{R}$ is volt.
(A) 100
(B) $\{(200) / \sqrt{2}\}$
(C) 200
(D) 280

Varsha Aggarwal
Varsha Aggarwal
Numerade Educator
03:21

Problem 2585

For a transistor, in a common base configuration the alternating current gain $\alpha$ is given by:
(A) $\left[\Delta \mathrm{I}_{\mathrm{C}} / \Delta \mathrm{I}_{\mathrm{B}}\right]_{(\mathrm{V}) \mathrm{C}=\mathrm{const}}$
(B) $\left[\Delta \mathrm{I}_{\mathrm{B}} / \Delta \mathrm{I}_{\mathrm{C}}\right]_{(\mathrm{V}) \mathrm{C}=\mathrm{const}}$
(C) $\left[\Delta \mathrm{I}_{\mathrm{C}} / \Delta \mathrm{I}_{\mathrm{E}}\right]_{(\mathrm{V}) \mathrm{C}=\text { const }}$
(D) $\left[\Delta \mathrm{I}_{\mathrm{E}} / \Delta \mathrm{I}_{\mathrm{C}}\right]_{(\mathrm{V}) \mathrm{C}=\text { const }}$

Aman Kumar
Aman Kumar
Numerade Educator
01:01

Problem 2586

In a N-P-N transistor circuit, the emitter, collector and base current are respectively $\mathrm{I}_{E}, I_{C}$ and $I_{B} .$ The relation between them is
(A) $\mathrm{I}_{\mathrm{C}}<\mathrm{I}_{\mathrm{E}}<\mathrm{I}_{\mathrm{B}}$
(B) $\mathrm{I}_{\mathrm{B}}<\mathrm{I}_{\mathrm{C}}<\mathrm{I}_{\mathrm{E}}$
(C) $\mathrm{I}_{\mathrm{B}}>\mathrm{I}_{\mathrm{C}}<\mathrm{I}_{\mathrm{E}}$
(D) $\mathrm{I}_{\mathrm{B}}>\mathrm{I}_{\mathrm{C}}>\mathrm{I}_{\mathrm{E}}$

Narayan Hari
Narayan Hari
Numerade Educator
00:52

Problem 2587

Assuming that the junction diode is ideal, the current through the diode is $\mathrm{mA}$
(A) 1
(B) 10
(C) 20
(D) 30

Varsha Aggarwal
Varsha Aggarwal
Numerade Educator
00:59

Problem 2588

The symbol represents:
(A) NOT gate
(B) OR gate
(C) AND gate
(D) NOR gate

Varsha Aggarwal
Varsha Aggarwal
Numerade Educator
01:25

Problem 2589

The combinations of NAND gates shown here under are equivalent to:
(A) OR gate and NOT gate
(B) AND gate and OR gate
(C) AND gate and NOT gate
(D) OR gate and AND gate

Varsha Aggarwal
Varsha Aggarwal
Numerade Educator
01:41

Problem 2590

How many NAND gates are used to form AND gate?
(A) 1
(B) 2
(C) 3
(D) 4

Varsha Aggarwal
Varsha Aggarwal
Numerade Educator
00:39

Problem 2591

Ripples are
(A) A.C. mixed with D.C
(B) D.C. mixed with output
(C) D.C. output
(D) A.C. output

Keshav Singh
Keshav Singh
Numerade Educator
01:12

Problem 2592

In an P.N.P transistor circuit, the collector current is $10 \mathrm{~mA}$. If $90 \%$ of the electrons emitted reach the collector:
(A) $\mathrm{I}_{\mathrm{E}}=9 \mathrm{~m} \mathrm{~A}$
(B) $\mathrm{I}_{\mathrm{E}}=10 \mathrm{~mA}$
(C) $\mathrm{I}_{\mathrm{B}}=1 \mathrm{~mA}$
(D) $\mathrm{I}_{\mathrm{B}}=-1 \mathrm{~mA}$

Varsha Aggarwal
Varsha Aggarwal
Numerade Educator
01:18

Problem 2593

When a P-type semi-conductor is heated:
(A) number of holes increases while that of electrons decreases
(B) number of electron increases while that of hole decreases
(C) number of electrons and holes remains same
(D) number of electrons and holes increases equally

Varsha Aggarwal
Varsha Aggarwal
Numerade Educator
02:17

Problem 2594

The depletion layer in PN junction diode is caused by
(A) drift of holes
(B) Diffusion of impurity ions
(C) diffusion of charge carriers
(D) drift of electrons

Aman Kumar
Aman Kumar
Numerade Educator
07:05

Problem 2595

The active junction area in a solar cell is as we want power
(A) small, more
(B) small, small
(C) large, more
(D) large, small

Nicole Hewett
Nicole Hewett
Numerade Educator
01:01

Problem 2596

The forbidden energy band gap in semi-conductor, conductor and insulator are $E_{1}, E_{2}$ and $E_{3}$ respectively. The relation among then is:
(A) $E_{1}<E_{2}>E_{3}$
(B) $\mathrm{E}_{1}>\mathrm{E}_{2}>\mathrm{E}_{3}$
(C) $E_{1}<E_{2}<E_{3}$
(D) $\mathrm{E}_{1}>\mathrm{E}_{2}<\mathrm{E}_{3}$

Varsha Aggarwal
Varsha Aggarwal
Numerade Educator
01:12

Problem 2597

An N-P-N Transistor circuit is shown in figure is
(A) A common base circuit
(B) A common emitter circuit
(C) A common collector circuit
(D) Oscillator circuit

Varsha Aggarwal
Varsha Aggarwal
Numerade Educator
01:23

Problem 2598

In a common emitter amplifier, output resistance is $5000 \Omega$ and input resistance is $1000 \Omega .$ If peak value of signal voltage is $1 \mathrm{mV}$ and $\beta=100$, then the peak value of output voltage is
(A) $0.1 \mathrm{~V}$
(B) $0.3 \mathrm{~V}$
(C) $0.2 \mathrm{~V}$
(D) $0.5 \mathrm{~V}$

Varsha Aggarwal
Varsha Aggarwal
Numerade Educator
01:02

Problem 2599

The A.C. current gain of a transistor is 100 . If the base current changes by $100 \mu \mathrm{A}$, What is the charge in collector current?
(A) $20 \mathrm{~mA}$
(B) $30 \mathrm{~mA}$
(C) $10 \mathrm{~mA}$
(D) $10 \mu \mathrm{A}$

Narayan Hari
Narayan Hari
Numerade Educator
00:45

Problem 2600

What is the output of the combination of the gates shown in the fig. below?
(A) $\mathrm{A}+\underline{\mathrm{A}} \cdot \mathrm{B}$
(B) $\mathrm{A}+\mathrm{A} \cdot \mathrm{B}$
(C) $(\mathrm{A}+\mathrm{B}) \cdot(\underline{\mathrm{A}} \cdot \mathrm{B})$
(D) $(\mathrm{A}+\mathrm{B}) \cdot(\underline{\mathrm{A}}+\mathrm{B})$

Varsha Aggarwal
Varsha Aggarwal
Numerade Educator
01:34

Problem 2601

The expression of $\mathrm{Y}$ in the following circuit is:
(A) $\mathrm{AB}+\mathrm{CD}$
(B) $\mathrm{A}+\mathrm{BCD}$
(C) $\mathrm{A}+\mathrm{B}+\mathrm{C}+\mathrm{D}$
(D) $\mathrm{A} \cdot \mathrm{B} \cdot \mathrm{C} \cdot \mathrm{D}$

Varsha Aggarwal
Varsha Aggarwal
Numerade Educator
02:19

Problem 2602

Which of the following figure represents an ideal diode characteristics?

Ajay Singhal
Ajay Singhal
Numerade Educator
10:26

Problem 2603

In Ge sample, traces of gallium are added as impurity. The resultant sample would behave like:
(A) a conductor
(B) a P-type semiconductor
(C) an N-type semiconductor
(D) an insulator

Shazia Naz
Shazia Naz
Numerade Educator
01:25

Problem 2604

A light emitting diode has a voltage drop of $2 \mathrm{~V}$ across it when $10 \mathrm{~mA}$ current is passed. If this $\mathrm{LED}$ is to be operated with $6 \mathrm{~V}$ battery the value of limiting resistor would be
(A) $400 \Omega$
(B) $4000 \Omega$
(C) $40 \mathrm{k} \Omega$
(D) $300 \Omega$

Ajay Singhal
Ajay Singhal
Numerade Educator
01:15

Problem 2605

NAND gate is
(A) A basic gate
(B) Not a universal gate
(C) A universal gate
(D) Multipurpose gate

Ajay Singhal
Ajay Singhal
Numerade Educator
02:18

Problem 2606

The number of holes and electrons in an intrinsic conductors are $\mathrm{x}$ and $\mathrm{y}$ respectively at room temperature. Which of the following options are true?
(A) $x>y$
(B) $\mathrm{y}>\mathrm{x}$
(C) $x=y$
(D) $x<<y$

Sachin Rao
Sachin Rao
Numerade Educator
01:49

Problem 2607

How will you increase the resistivity of Ge semi-conductor?
(A) On adding donor impurity
(B) On adding acceptor impurity
(C) On making UV light incident on Ge crystal
(D) On decreasing the temperature

Ajay Singhal
Ajay Singhal
Numerade Educator
01:01

Problem 2608

What is type of material, for the energy band diagram shown in the figure?
(A) N-type semi-conductor
(B) P-type semi-conductor
(C) Insulator
(D) Intrinsic semi-conductor

Ajay Singhal
Ajay Singhal
Numerade Educator
02:11

Problem 2609

From the following semi-conductor devices, operates in forward bias only.
(A) Varactar diode
(B) Zenger diode
(C) Light emitting diode
(D) photo-diode

Aman Kumar
Aman Kumar
Numerade Educator
01:29

Problem 2610

device is the odd-one out.
(A) solar-cell
(B) Varactor diode
(C) Photodiode
(D) Zenger diode

Arpit Gupta
Arpit Gupta
Numerade Educator
01:53

Problem 2611

The value of depletion capacitance on decreasing the reverse bias on varactor diode
(A) decreases
(B) increases
(C) becomes zero
(D) does not change

Aman Kumar
Aman Kumar
Numerade Educator
01:59

Problem 2612

Which of the following statement is correct for transistor $\mathrm{LC}$ oscillator circuit?
(A) It works with negative feed back
(B) The phase difference between output and input signal is $\pi$ radian
(C) To start oscillation external signal is required
(D) The frequency of output signal is independent of the components used in feedback circuit

Mahendra Kumar
Mahendra Kumar
Numerade Educator
01:52

Problem 2613

The frequency of output signal of LC oscillator circuit is $100 \mathrm{~Hz}$ with capacitance value $0.1 \mu \mathrm{F}$. If value of capacitance is taken as $0.2 \mu \mathrm{F}$, the frequency of output signal
(A) decreases by $(1 / \sqrt{2})$
(B) increases by $(1 / \sqrt{2})$
(C) decreases by $(1 / 2)$
(D) increases by $(1 / 2)$

Aja S
Aja S
Numerade Educator
01:21

Problem 2614

The Common Emitter amplifier has voltage gain equal to 300 and its input signal is $0.5 \cos (100 t)$ volt. The output signal will be equal to
(A) $150 \cos (100 \mathrm{t})$
(B) $300 \cos (100 \mathrm{t})$
(C) $150 \cos (100 t+\pi)$
(D) $300 \cos (100 t-\pi)$

Ajay Singhal
Ajay Singhal
Numerade Educator
02:31

Problem 2615

Common base current gain of a NPN transistor is $0.99$. The input resistance is $1000 \Omega$ and load resistance is $10,000 \Omega$. The voltage gain in common emitter mode is
(A) 9900
(B) 99000
(C) 99
(D) $\overline{990}$

Aman Kumar
Aman Kumar
Numerade Educator
01:26

Problem 2616

The logic circuit shown in the figure, is the equivalent diagram of which logic gate?
(A) OR gate
(B) NAND gate
(C) AND gate
(D) NOR gate

Ajay Singhal
Ajay Singhal
Numerade Educator
01:01

Problem 2617

In forward bias made, the PN junction diode resistance will
(A) infinity
(B) zero
(C) less
(D) more

Narayan Hari
Narayan Hari
Numerade Educator
01:41

Problem 2618

To obtain OR gate from NOR gate, you will need
(A) one NOR gate
(B) one NOT gate
(C) Two NOR gate
(D) one OR gate

Varsha Aggarwal
Varsha Aggarwal
Numerade Educator
01:10

Problem 2619

For Boolean identities match the pair:
(1) $\underline{\underline{A}}$
(P) $\underline{\mathrm{A}}+\underline{\mathrm{B}}$
(2) $\underline{\mathrm{A}+\mathrm{B}}$
(Q) A \cdot B
(3) $\underline{\mathrm{A} \cdot \mathrm{B}}$
(R) $\underline{A} \cdot \underline{B}$
(4) $\mathrm{A} \cdot(\underline{\mathrm{A}}+\mathrm{B})$
(S) $\mathrm{A}$
(A) $(1)-(\mathrm{S}),(2)-(\mathrm{P}),(3)-(\mathrm{Q}),(4)-(\mathrm{R})$
(B) $(1)-(\mathrm{S}),(2)-(\mathrm{R}),(3)-(\mathrm{Q}),(4)-(\mathrm{P})$
(C) (1) - (S), (2) - (Q), (3) - (P), (4) - (R)
(D) $(1)-(\mathrm{S}),(2)-(\mathrm{R}),(3)-(\mathrm{P}),(4)-(\mathrm{Q})$

Manik Pulyani
Manik Pulyani
Numerade Educator
01:37

Problem 2620

The ratio of concentration of electrons and holes in a semi-conductor is $(7 / 5)$ and the ratio of currents is $(7 / 4)$, then what is the ratio of their drift velocities?
(A) $(4 / 5)$
(B) $(5 / 6)$
(C) $(4 / 5)$
(D) $(5 / 4)$

Aman Kumar
Aman Kumar
Numerade Educator
02:15

Problem 2621

In a P-type silicon, which of the following statement is true?
(A) Electrons are majority charge carries and trivalent atoms are the dopants
(B) Electrons are minority charge carries and pentavalent atoms are dopants
(C) Holes are minority charge carries and pentavalent atoms are dopants
(D) Holes are majority charge carries and trivalent atoms are dopants

Nishant Kumar
Nishant Kumar
Numerade Educator
02:00

Problem 2622

In the circuit below $\mathrm{A}$ and $\mathrm{B}$ represents two inputs and $\mathrm{C}$ represents output. The circuit represents
(A) NOR gate
(B) NAND gate
(C) AND gate
(D) OR gate

Aman Kumar
Aman Kumar
Numerade Educator
01:39

Problem 2623

A zener diode used as voltage regulator is connected
(i) in forward bias
(ii) in reverse bias
(iii) in parallel with load (iv) in series with load
(A) (i) and (ii) are correct
(B) (ii) and (iii) are correct
(C) only (i) is correct
(D) only (iv) is correct

Varsha Aggarwal
Varsha Aggarwal
Numerade Educator
01:21

Problem 2624

A n-p-n transistor is used in common emitter mode in an amplifier it. A change of $40 \mu \mathrm{A}$ in the base current changes the output current by $2 \mathrm{~m} \mathrm{~A}$ and $0.04 \mathrm{~V}$ in input voltage.
The input resistance is
(A) $1 \mathrm{k} \Omega$
(B) $10 \Omega$
(C) $10 \mathrm{k} \Omega$
(D) $100 \Omega$

Ajay Singhal
Ajay Singhal
Numerade Educator
01:20

Problem 2625

A n-p-n transistor is used in common emitter made in an amplifier it. A change of $40 \mu \mathrm{A}$ in the base current changes the output current by $2 \mathrm{~mA}$ and $0.04 \mathrm{~V}$ in input voltage.
The current amplification factor is
(A) 20
(B) 30
(C) 50
(D) 400

Ajay Singhal
Ajay Singhal
Numerade Educator
01:21

Problem 2626

A n-p-n transistor is used in common emitter made in an amplifier it. A change of $40 \mu \mathrm{A}$ in the base current changes the output current by $2 \mathrm{~mA}$ and $0.04 \mathrm{~V}$ in input voltage.
If a load of $6 \mathrm{k} \Omega$ is used, then the voltage gain of the amplifier is
(A) 100
(B) 200
(C) 300
(D) 400

Ajay Singhal
Ajay Singhal
Numerade Educator
02:01

Problem 2627

A n-p-n transistor is used in common emitter made in an amplifier it. A change of $40 \mu \mathrm{A}$ in the base current changes the output current by $2 \mathrm{~mA}$ and $0.04 \mathrm{~V}$ in input voltage.
An amplifier has voltage gain $A_{V}=1000$. The voltage gain in $\mathrm{dB}$ is
(A) $20 \mathrm{~dB}$
(B) $30 \mathrm{~dB}$
(C) $3 \mathrm{~dB}$
(D) $60 \mathrm{~dB}$

Aman Kumar
Aman Kumar
Numerade Educator
01:15

Problem 2628

A potential barrier of $0.6 \mathrm{~V}$ exists across a P-N junction. If the depletion region is $1 \mu \mathrm{m}$ wide, what is the intensity of electric field in the region?
(A) $4 \times 10^{5} \mathrm{Vm}^{-1}$
(B) $5 \times 10^{5} \mathrm{Vm}^{-1}$
(C) $6 \times 10^{5} \mathrm{Vm}^{-1}$
(D) $2 \times 10^{5} \mathrm{Vm}^{-1}$

Ajay Singhal
Ajay Singhal
Numerade Educator
01:02

Problem 2629

when a PN junction diode is forward biased, then the lepletion region is and barrier height is
(A) reduced, increases
(B) widened, reduced
C) reduced, reduced
(D) increased, increased

Narayan Hari
Narayan Hari
Numerade Educator
02:35

Problem 2630

Which of the following circuit provides full wave rectification?

Vishal Gupta
Vishal Gupta
Numerade Educator
01:21

Problem 2631

A common-emitter amplifier has a voltage gain of 100 , an input impedance of $100 \Omega$ and an output impedance of $200 \Omega$. The product of voltage gain and current gain is
(A) 1000
(B) 3000
(C) 5000
(D) 500

Ajay Singhal
Ajay Singhal
Numerade Educator
02:03

Problem 2632

A P-N photodiode is made of a material with a band gap of 2.0ev. The minimum frequency of the radiation that can be absorbed by the material is nearly (Take hc $=1240 \mathrm{eVnm}$ )
(A) $5 \times 10^{14} \mathrm{~Hz}$
(B) $20 \times 10^{14} \mathrm{~Hz}$
(C) $1 \times 10^{14} \mathrm{~Hz}$
(D) $10 \times 10^{14} \mathrm{~Hz}$

Yuva S
Yuva S
Numerade Educator
01:02

Problem 2633

The bolean equation for the circuit is
(A) $\mathrm{Y}=\underline{\mathrm{A}} \cdot \mathrm{B}+\mathrm{C}$
(B) $\mathrm{Y}=\underline{\mathrm{A}} \cdot(\mathrm{B}+\mathrm{C})$
(C) $\mathrm{Y}=\underline{\mathrm{A}}(\underline{\mathrm{B}}+\underline{\mathrm{C}})$
(D) $\mathrm{Y}=\underline{\mathrm{A}} \cdot(\mathrm{B}+\underline{\mathrm{C}})$

James Kiss
James Kiss
Numerade Educator
01:44

Problem 2634

A n-p-n transistor circuit has $\alpha=0.985 .$ If $\mathrm{I}_{\mathrm{c}}=9 \mathrm{~mA}$ then the value of $\mathrm{I}_{\mathrm{b}}$ is
(A) $0.003 \mathrm{~mA}$
(B) $0.66 \mathrm{~mA}$
(C) $0.015 \mathrm{~mA}$
(D) $0.13 \mathrm{~mA}$

Chai Santi
Chai Santi
Numerade Educator
01:26

Problem 2635

For a transistor amplifier, the voltage gain
(A) remains constant for all frequencies
(B) is high at high and low frequencies and constant in the mid-frequency range
(C) is low at high and low frequencies and constant in the mid-frequency range
(D) None of the above

Nishant Kumar
Nishant Kumar
Numerade Educator
01:37

Problem 2636

The current flowing through $10 \Omega$ resistor in the circuit shown in the figure is
(A) $50 \mathrm{~mA}$
(B) $20 \mathrm{~mA}$
(C) $40 \mathrm{~mA}$
(D) $80 \mathrm{~mA}$

Ajay Singhal
Ajay Singhal
Numerade Educator
01:14

Problem 2637

The input and outputs from different time intervals are given below for NAND gate
The value taken by $\mathrm{P}, \mathrm{Q}, \mathrm{R}$ and $\mathrm{S}$ are respectively
(A) $1,0,1,1$
(B) $0,1,0,0$
(C) $0,1,0,1$
(D) $1,1,1,0$

Ajay Singhal
Ajay Singhal
Numerade Educator
02:44

Problem 2638

The manifestation of band structure in solids is due to:
(A) Heisenberg's uncertainty principle
(B) Pauli's exclusion principle
(C) Bohr's correspondence principle
(D) Boltzmann's low

Aman Kumar
Aman Kumar
Numerade Educator
01:46

Problem 2639

Copper and silicon material is cooled down from $600 \mathrm{~K}$ to $400 \mathrm{~K}$ then, resistivity of cooper and silicon
(A) increases, decreases
(B) decreases, increases
(C) decreases, decreases
(D) increase, increases

Ajay Singhal
Ajay Singhal
Numerade Educator
01:51

Problem 2640

Semi-conductor has phosphorus as impurity then it will have
(A) $\mathrm{n}_{\mathrm{e}}>\mathrm{n}_{\mathrm{h}}$
(B) $\mathrm{n}_{\mathrm{e}}<<\mathrm{n}_{\mathrm{h}}$
(C) $\mathrm{n}_{\mathrm{e}}=\mathrm{n}_{\mathrm{h}}$
(D) $n_{e}=n_{h}=n_{i}$

Cathy Geisel
Cathy Geisel
Numerade Educator
01:32

Problem 2641

Zener diode is used as
(A) Full. wave rectifier
(B) amplifier
(C) A.C. voltage regulator
(D) D.C. voltage regulator

Aman Kumar
Aman Kumar
Numerade Educator
01:03

Problem 2642

Break down voltage of a diode is $5 \mathrm{~V}$. By which effect this breakdown occurs in diode?
(A) Only avalanche effect
(B) Only zener effect
(C) Avalanche or zener effect
(D) None of the above

Narayan Hari
Narayan Hari
Numerade Educator
02:33

Problem 2643

When NPN transistor is used as an amplifier then
(A) electron moves from base to collector
(B) hole travels from emitter to base
(C) hole goes to emitter from base
(D) electron goes to base from collector

Ajay Singhal
Ajay Singhal
Numerade Educator
02:11

Problem 2644

For a given amplifier circuit, to make transistor active as an amplifier, how much value of voltages to be kept for $\mathrm{V}_{\mathrm{BB}}$ battery and $\mathrm{V}_{\mathrm{CC}}$ battery?
(A) $\mathrm{V}_{\mathrm{BB}}=-1 \mathrm{~V} \mathrm{~V}_{\mathrm{CC}}=+5 \mathrm{~V}$
(B) $\mathrm{V}_{\mathrm{BB}}=-1 \mathrm{~V} \mathrm{~V}_{\mathrm{CC}}=-5 \mathrm{~V}$
(C) $\mathrm{V}_{\mathrm{BB}}=+1 \mathrm{~V} \mathrm{~V}_{\mathrm{CC}}=+5 \mathrm{~V}$
(D) $\mathrm{V}_{\mathrm{BB}}=+1 \mathrm{~V} \mathrm{~V}_{\mathrm{CC}}=-5 \mathrm{~V}$

Ben Nicholson
Ben Nicholson
Numerade Educator
02:01

Problem 2645

Which of the following logic gate will have output $1 ?$

AK
Ankur Khosla
Numerade Educator
01:21

Problem 2646

For gate, the output is 1 only when both input are ' $\mathrm{O}^{\prime}$
(A) AND
(B) NAND
(C) $\mathrm{OR}$
(D) NOR

Varsha Aggarwal
Varsha Aggarwal
Numerade Educator
01:23

Problem 2647

In VLSI circuits more than gates are contained.
(A) 1000
(B) 100
(C) 10
(D) 500

Varsha Aggarwal
Varsha Aggarwal
Numerade Educator
01:21

Problem 2648

The flow of valence electrons to the left means that holes are flowing.
(A) Left
(B) Right
(C) Either way
(D) None

Ajay Singhal
Ajay Singhal
Numerade Educator
01:18

Problem 2649

How many free electrons does a P-type semiconductor contain?
(A) Many
(B) None
(C) Only those produced by thermal energy
(D) Same number as holes

Varsha Aggarwal
Varsha Aggarwal
Numerade Educator
01:47

Problem 2650

Suppose an intrinsic semi-conductor at room temperature has 1 billion free electrons at room temperature. If temperature changes to $75^{\circ} \mathrm{C}$, how many holes are there?
(A) Fewer than 1 billion
(B) 1 billion
(C) More than 1 billion
(D) Impossible to say

Ajay Singhal
Ajay Singhal
Numerade Educator
02:27

Problem 2651

Which of the following doesn't fit in the group?
(A) Conductor
(B) Semi conductor
(C) Four valence electrons
(D) Crystal structure

Shazia Naz
Shazia Naz
Numerade Educator
01:28

Problem 2652

What kind of device is a diode?
(A) Bilateral
(B) Linear
(C) Nonlinear
(D) Unipolar

Ajay Singhal
Ajay Singhal
Numerade Educator
02:01

Problem 2653

We want a peak load voltage of $40 \mathrm{~V}$ out of a bridge rectifier, What is the approximate rms value of secondary voltage?
(A) $0 \mathrm{~V}$
(B) $14.4 \mathrm{~V}$
(C) $28.3 \mathrm{~V}$
(D) $56.6 \mathrm{~V}$

DW
David Walther
Numerade Educator
01:39

Problem 2654

The load voltage is approximately constant when a zener diode is
(A) Forward biased
(B) Reverse biased
(C) Operating in breakdown region
(D) Unbiased

Varsha Aggarwal
Varsha Aggarwal
Numerade Educator
01:39

Problem 2655

When source voltage increases in a zener diode, which of these current remains approximately constant?
(A) Series current
(B) Zener current
(C) Load current
(D) Total current

Varsha Aggarwal
Varsha Aggarwal
Numerade Educator
01:15

Problem 2656

The device associated with voltage controlled capacitance is
(A) Light emitting diode
(B) Photo diode
(C) Varactor diode
(D) Zener diode

Ajay Singhal
Ajay Singhal
Numerade Educator
01:30

Problem 2657

For normal operation of the transistor, the collector diode has to be
(A) Forward biased
(B) Reverse biased
(C) Non conducting
(D) Operating in breakdown region

Ajay Singhal
Ajay Singhal
Numerade Educator
02:33

Problem 2658

Most of the electrons in the base of N-P-N transistor flow
(A) Out of the base lead
(B) Into the collector
(C) Into the emitter
(D) Into the base supply

Ajay Singhal
Ajay Singhal
Numerade Educator
01:41

Problem 2659

Direction for Assertion - Reason type questions
(A) If both Assertion and Reason are true and reason is the correct explanation of assertion.
(B) If both Assertion and Reason are true but Reason is not the correct explanation of assertion.
(C) If Assertion is true but Reason is false
(D) If both assertion and reason are false
A: Intrinsic charge carries are thermally generated
$\mathrm{R}$ : Their availability can be easily controlled
(A) a
(B) b
(C) $\mathrm{c}$
(D) d

Prem Bijarniya
Prem Bijarniya
Numerade Educator
01:41

Problem 2660

Direction for Assertion - Reason type questions
(A) If both Assertion and Reason are true and reason is the correct explanation of assertion.
(B) If both Assertion and Reason are true but Reason is not the correct explanation of assertion.
(C) If Assertion is true but Reason is false
(D) If both assertion and reason are false
A: Impurity atoms for silicon is selected from third or fifth group
$R$ : These Impurity atoms have same size as that of $\mathrm{Si}$
(A) a
(B) $b$
(C) c
(D) d

Prem Bijarniya
Prem Bijarniya
Numerade Educator
01:40

Problem 2661

Direction for Assertion - Reason type questions
(A) If both Assertion and Reason are true and reason is the correct explanation of assertion.
(B) If both Assertion and Reason are true but Reason is not the correct explanation of assertion.
(C) If Assertion is true but Reason is false
(D) If both assertion and reason are false
A: Photodiode are operated in reverse bias
$\mathrm{R}$ : In reverse bias fractional change in minority charge carrier is more
(A) a
(B) $b$
(C) c
(D) $\mathrm{d}$

Prem Bijarniya
Prem Bijarniya
Numerade Educator
01:40

Problem 2663

Direction for Assertion-Reason type questions
(A) If both Assertion and Reason are true and reason is the correct explanation of assertion.
(B) If both Assertion and Reason are true but Reason is not the correct explanation of assertion.
(C) If Assertion is true but Reason is false
(D) If both assertion and reason are false
A : NAND (or NOR) gates are called digital building blocks
$\mathrm{R}$ : The different combination of NAND (or NOR) gates can produce all the basic or complicated gates.
(A) a
(B) $b$
(C) $\mathrm{c}$
(D) d

Prem Bijarniya
Prem Bijarniya
Numerade Educator
02:02

Problem 2664

Direction for Assertion - Reason type questions
(A) If both Assertion and Reason are true and reason is the correct explanation of assertion.
(B) If both Assertion and Reason are true but Reason is not the correct explanation of assertion.
(C) If Assertion is true but Reason is false
(D) If both assertion and reason are false
A: The colour of light emitted by depends on its forward bias.
$\mathrm{R}$ : The forward biasing of PN junction diode will increase the width of depletion layer
(A) a
(B) $b$
(C)
(D) $\mathrm{d}$

Prem Bijarniya
Prem Bijarniya
Numerade Educator
01:41

Problem 2665

Direction for Assertion - Reason type questions
(A) If both Assertion and Reason are true and reason is the correct explanation of assertion.
(B) If both Assertion and Reason are true but Reason is not the correct explanation of assertion.
(C) If Assertion is true but Reason is false
(D) If both assertion and reason are false
A: The ionization energy of isolated phosphorous is very large
$\mathrm{R}$ : The ionization energy of phosphorous in lattice is very small
(A) a
(B) $b$
(C) $\mathrm{c}$
(D) $\mathrm{d}$

Prem Bijarniya
Prem Bijarniya
Numerade Educator
01:20

Problem 2666

Direction for Assertion - Reason type questions
(A) If both Assertion and Reason are true and reason is the correct explanation of assertion.
(B) If both Assertion and Reason are true but Reason is not the correct explanation of assertion.
(C) If Assertion is true but Reason is false
(D) If both assertion and reason are false
A: Mostly transistor are used in common emitter configuration
$\mathrm{R}$ : Common emitter configuration provide more current gain and small voltage gain
(A) a
(B) b
(C) $\mathrm{c}$
(D) $d$

Prem Bijarniya
Prem Bijarniya
Numerade Educator
01:20

Problem 2667

Direction for Assertion - Reason type questions
(A) If both Assertion and Reason are true and reason is the correct explanation of assertion.
(B) If both Assertion and Reason are true but Reason is not the correct explanation of assertion.
(C) If Assertion is true but Reason is false
(D) If both assertion and reason are false
A : A transistor amplifier circuit in common emitter configuration has low input impedance
$\mathrm{R}$ : Base-emitter junction is forward biased
(A)
(B)
(C)
(D)

Prem Bijarniya
Prem Bijarniya
Numerade Educator