ELECTROMAGNETIC FIELDS AND TRANSMISSION LINES (EMTL) IMPORTANT QUESTIONS

SHORT QUESTIONS

1. State and explain Coulomb’s law

2. State Gauss law and mention its applications

3. What is continuity equation?

4. Define Ampere's circuital Law

5. Why Ampere’s law is inconsistent?

6. What is the significance of Ampere’s force law?

7. Define magnetic flux density

8. State Biot-Savarts Law?

9. Define Displacement current Density

10. Define displacement current.

11. Define Faraday,s Law

12. State the Poynting Theorem.

13. Define Polarization and its types

14. Define Brewster Angle and also write the equation.

15. Write the relationship between phase and group velocities

16. List out various types of Transmission Lines

17. What is the use of smith chart?

18. Write the condition for Distortion less line & Minimum Attenuation

LONG QUESTIONS

1. Derive the Electric Field Intensity of line charge distribution

2. (a) Define Coulomb’s law and derive the force F that exists between two unlike charges. (b)Three Point Charges Q1=1 mc, Q2=2 mc and Q3=-3 mc are respectively located at (0,0,4), (-2,6,1) and (3, -4, -8). Calculate the electric force and electric field on Q1 due to Q2 and Q3.

3. Define Gauss’s Law. Apply Gauss’s law to evaluate Electric Flux density for a uniformly charged Sphere.

4. Derive the equation for Continuity Equation & Relaxation time

5. Explain Biot Savarts’ law and Magnetic Flux density

6. Derive and explain in detail the Maxwell's equations in point form and integral form.

7. a) Distinguish between good conductors and good dielectrics. Explain the wave propagation

b) Explain about boundary conditions at dielectric – conductor interface.

8. A Positive Y-axis (Semi Infinite Line with respect to the Origin) Carries a Filamentary Current of 2 A in the -ay Direction. Assume it is part of a large circuit. Find H at (i) A(2,3,0). (ii) B(3,12,-4),

9. Derive the Magnetic Field Intensity due to line current

10. State and prove the Ampere’s circuits law & Give the equations for Magnetic vector potential

11. a) Define polarization of an electromagnetic wave and explain different type of polarizations with examples. b) Represent a typical left circularly polarized wave by an expression.

12. Derive the Maxwell’s equations for time varying fields in point form, integral and also give word statements

13. Derive the Boundary conditions for Dielectric-Dielectric

14. What is Brewster Angle? Derive the Brewster angle for parallel polarization

15. Derive the relation between E & H for Uniform Plane Waves

16. Derive Reflection and Refraction of Plane waves - Normal Incidences for Perfect Dielectrics

17. Derive the voltage (V) and current (I) equations of a transmission line in terms of R, L, C and G and explain?

18. Given R=10.4 Ω/m, L=0.00367H/m, G=0.8x10^-4 S/m and C=0.00835µF/m. Calculate Z₀ and ɣ at 1 KHz.

19. Derive the equation for voltage and current at any point in a transmission line

20. A 30 m long lossless transmission line with Z₀ = 50Ω operating at 2 MHz is terminated with a load Z_L = 60 + j 40Ω. If u = 0.6 C on the line, find the reflection coefficient, the standing wave ratio S and the input impedance. (i) without using smith chart (ii) Using smith chart

NETWORK ANALYSIS AND SYNTHESIS (NAS) LONG ANSWER QUESTIONS.

LONG ANSWER QUESTIONS

UNIT-I, NETWORK TOPOLOGY

1. For the following network,

 i) Draw graph.

 ii) Determine the incidence matrix.

 iii) Determine the cutest matrix.

2. What is dot convention? For the following circuit, Determine currents I₁ and I₂.

3. a) Obtain an expression for coefficient of coupling.

 b) Two coils A and B having turns 100 and 1000 respectively are wound side by side on closed circuit coil of X-section 8 cm2 and mean length 80 cm. The relative permeability of iron is 900. Calculate the mutual inductance between the coils.

4. Define coefficient of coupling and derive the relationship between self-inductances of two coils, mutual inductance between them and the coefficient of coupling.

5. For the given graph of network is shown in figure, write the

 (i) incidence Matrix

 (ii) f-cutset Matrix

6. For the circuit shown in Figure, draw the oriented graph and write the following.

 (i) Incidence Matrix.

 (ii) f-cutset Matrix.

 (iii) Tieset Matrix.

7. Explain Self Inductance, Mutual Inductance and Co-efficient of coupling in detail? Give the relation between L1, L2, K & M?

8. Derive the coefficient of coupling for coupled circuits.

UNIT-II, TRANSIENT AND STEADY STATE ANALYSIS

1. a) Derive and draw the transient response of i(t) for a series RLC circuit with step input considering the critically damped case.

1. b) Explain RC circuit acting as a differentiator.

2. Derive the expression for i(t) of R-C series circuit when DC voltage in applied to it at t=0 by closing the switch. Define time constant of R-C circuit.

3. Derive the expression for i(t) of R-L series circuit when DC voltage in applied to it at t=0 by closing the switch. Define time constant of R-L circuit.

4. A coil having an inductance of 50 mH and resistance of 10 ohms is connected in series with a 25 μF capacitor across 200 V AC supply. Calculate: i) Resonant frequency ii) Current flowing at resonance iii) Quality factor

5. Obtain the expression for resonant frequency, bandwidth and Q-factor for Series R-L-C circuit.

6. a) Derive and draw the transient response of i(t) for a series RLC circuit with step input considering the under damped case.

6. b) Explain RC circuit acting as an integrator.

7. A series RLC circuit takes a maximum current of 0.3 A at 200 V, 50 Hz. If the voltage across the capacitor is 290V at resonance. Determine R,L,C and Q of the coil.

8. Obtain the expression for transient current in a R-L circuit is suddenly connected with a unit step function by closing the switch at t = 0.

UNIT-III, TWO PORT NETWORK PARAMETERS

1. a) Explain the Y-parameters for a two-port network with suitable example.

 b) Determine the h- Parameters for the following data:

  (i) With output shorted: V₁=25V, I₁=1A,I₂=2A

  (ii)With input terminals open circuited: V₁=10V, V₂=50V,I₂=2A

2. a) Explain the Z-parameters for a two-port network with suitable example.

 b) Determine the h- Parameters for the following data:

  (i) With output shorted: V₁=25V, I₁=1A, I₂=2A

  (ii)With input terminals open circuited: V₁=10V, V₂=50V, I₂=2A

3. Obtain Z parameters.

4. a) Explain about Impedance parameters.

 b) Find the transmission parameters for the circuit shown in figure.

5. a) Derive the expressions for Y-parameters in terms of ABCD parameters.

 b) Determine the y-parameters of the following network.

6. Derive the expressions for Y-parameters in terms of ABCD parameters.

7. a) Explain π to T transformation for two port networks.

 b) Obtain the ABCD parameters of the following network

8. a) Explain T to π transformation for two port networks.

 b) Obtain the ABCD parameters of the following network

UNIT-IV, FILTERS AND ATTENUATORS

1. a) Design a band pass filter with cutoff frequencies of 2000 Hz and 5000Hz with a design impedance of 500 ohms.

 b) Derive the expression for cut-off frequency for low-pass filter.

2. Design m-derived low pass filter having cut off frequency of 1 KHz, design impedance of 400 ohm, and the resonant frequency 1100 KHz.

3. a) Derive the expression for characteristic impedance in a pass band filter

 b) Design an m-derived T section low pass filter having a design impedance of 800 Ω, cut-off frequency of 4400 Hz and infinite attenuation at 2500 Hz.

4. Derive the design equations of symmetrical T attenuator and design it with a characteristic impedance of 200 Ω yielding an attenuation of 40 dB.

5. Explain about Constant-K high-pass filter in detail.

6. a) Explain about Propagation constant and Characteristic impedance in Π-network filters.

 b) Design Low Pass Filter in both T& Π section having a cut off frequency of 2KHz to operate with a terminated load resistance of 500 Ω

7. Explain about Constant-K low-pass filter in detail.

8. a) Explain about classification of filters.

 b) Explain about Propagation constant and Characteristic impedance in T-network filters.

UNIT-V, NETWORK SYNTHESIS

1. Determine the driving-point impedance and driving point admittance of the network shown in following Figure.

2. Find the first and second forms of Causer network for the function (s²+5s+4) / (s²+2s)

3. Test whether the following function is positive real or not.

4. Realize the Foster I and II forms of the following function

5. Explain the concept of elementary synthesis

 a) Removal of a pole at infinity

 b) Removal of a pole at origin.

6. a) Write the properties of Positive real function

 b) Determine whether P(s)= S⁴+S³+2S²+3S+2 is Hurwitz.

NETWORK ANALYSIS AND SYNTHESIS (NAS) SHORT ANSWER QUESTIONS.

SHORT ANSWER QUESTIONS

UNIT-I, NETWORK TOPOLOGY

1. Define the Planner Networks and Non-Planner networks.

2. Define the Mutual Inductance.

3. Define the self inductance

4. Define Faraday’s Laws of Electro Magnetic Induction?

5. Distinguish between self-inductance and mutual inductance.

6. What is the use of tie-set matrix of a network?

7. What is a fundamental cut set matrix?

8. What is an ideal transformer?

UNIT-II, TRANSIENT AND STEADY STATE ANALYSIS

1. Draw the admittance characteristics of a parallel resonant circuit

2. What is the behavior of Inductor in Initial and Steady state conditions?

3. What is the condition for resonance for an RLC series circuit?

4. Define the Planner Networks and Non-Planner networks.

5. Define Quality-factor and Selectivity.

6. What is the behavior of capacitor in Initial and Steady state conditions?

7. Define damping factor?

8. What is the bandwidth of a resonant circuit?

UNIT-III, TWO PORT NETWORK PARAMETERS

1. Define Two-port network.

2. What you mean by open circuit Impedance.

3. What is the condition for Symmetry in Z and Y parameters?

4. What are the properties of a driving point function?

5. Write the expressions for Y-parameters in terms of Z

6. What is the condition for Reciprocity in Z and Y parameters?

7. Write briefly about Characteristic Impedance

8. Write the expressions for Z-parameters in terms of Y

UNIT-IV, FILTERS AND ATTENUATORS

1. Draw the characteristics of Low-pass and High-pass filters.

2. Define Propagation constant.

3. Draw the block diagram of band-pass and band-elimination filters.

4. Draw the characteristics of Low-pass and High-pass filters.

5. List the de-merits of M-derived filters.

6. Differentiate between low pass and high pass filters

7. What are the characteristics of network equalizers?

8. Classify constant K-filters.

UNIT-V, NETWORK SYNTHESIS

1. Define Transfer admittance.

2. What is driving point admittance ?

3. What is driving point impedance?

4. Write the Non-ladder network.

5. What is network synthesis?

6. What is a positive real function?

7. Define transfer impedance.

8. Write the ladder network.

NAS - MID-I PRACTICE QUESTIONS

MULTIPLE CHOICE QUESTION AND ANSWERS

======================================================================

1. A graph is said to be a directed graph if ________ of the graph has direction.

A) 1 branch
B) 2 branch
C) 3 branch
D) every branch

Answer is D)

Explanation:
If every branch of the graph has direction, then the graph is said to be a directed graph. If the graph does not have any direction then that graph is called undirected graph.

2. If the current in one coil becomes steady, the current in neighboring coil is?

A) Zero
B) Infinity
C) Double
D) Halves
Answer is A)
A current is induced when there is changing magnetic flux. Hence the induced current in neighbouring coil is zero when the current is steady.

3. If no two branches of the graph cross each other, then the graph is called?

A) directed graph
B) undirected graph.
C) planar graph.
D) non-planar graph.
Answer is C)
Explanation: If a graph can be drawn on a plane surface such that no two branches of the graph cross each other, then the graph is called planar graph.

4. If the flux linkage in coil 1 is 3Wb and it has 500 turns and the current in coil 2 is 2A, calculate the mutual inductance..

A) 750H
B) 650H
C) 550H
D) 450H

Answer is A)

Explanation: We know that mutual inductance is the product of the number of turns in one coil and the flux linkages of that coil, divided by the current in the other coil. M=3*500/2=750H..

5.The flux linkage in coil 1 is 3Wb and it has x turns and the current in coil 2 is 2A, calculate the value of x if the mutual inductance is 750H.

A) 300 Turns
B) 400 Turns
C) 500 Turns
D) 600 Turns

Answer is C)

Explanation: We know that mutual inductance is the product of the number of turns in one coil and the flux linkages of that coil, divided by the current in the other coil. N=750*2/3 = 500 turns..

6. What is the direction of the cut-set?

A) same as the direction of the branch current
B) opposite to the direction of the link current
C) same as the direction of the link current
opposite to the direction of the branch current

Answer is A)

Explanation: A cut-set is a minimal set of branches of a connected graph such that the removal of these branches causes the graph to be cut into exactly two parts. The direction of the cut-set is same as the direction of the branch current.

7. Practical application of mutual inductance is ____________

A) DC Generator
B) AC Generator
C) Transformer
D) Capacitor

Answer is C)

Explanation: A transformer is a device made of two or more inductors, one of which is powered by AC, inducing an AC voltage across the second inductor.

8 Tie-set is also called?

A) e loop loop
B) f loop
C) g loop
D) h loop

Answer is B)

Explanation: The fundamental loop formed by one link has a unique path in the tree joining the two nodes of the link. This loop is also called f-loop.

9. What is the coupling coefficient when there is ideal coupling?

A) 0
B) 1
C) 100
D) insufficient information provided

Answer is B)

Explanation: When all the flux of coil 1 links with coil 2 it is known as an ideal coupling where the coupling coefficient is 1.

10. Number of twigs in a tree are? (where, n-number of nodes)

A) n
B) n + 1
C) n - 1
D) n - 2

Answer is C)

Explanation: Twig is a branch in a tree. Number of twigs in a tree are n-1. If there are 4 nodes in a tree then number of possible twigs are 3.

11. The number of branches incident at the node of a graph is called?

A) degree of the node
B) order of the node
C) status of the node
D) number of the nodes

Answer is A)

Explanation: Nodes can be incident to one or more elements. The number of branches incident at the node of a graph is called degree of the node.

12. Can the coupling coefficient practically ever be equal to 1?

A) YES
B) NO
C) Depends on the current in coil 1
D) Depends on the current in coil 2

Answer is B)

Explanation: All the flux of coil 1 can never link with coil 2. Loss occurs practically due to which coupling coefficient cannot be equal to 1.

13. A portion of a graph is called _______.

A) Branch
B) Links
C) Tree
D) None of these

Answer is C)

Explanation: A portion of the graph is called tree.

14. A RC integrator is also known as ____________________.

A) Band pass filter
B) All pall filter
C) High pass filter
D) Low pass filter

Answer is D)

Explanation:The RC type Integrator is a type of Low Pass Filter.

15.A RC Differentiator is also known as ____________________.

A) Band pass filter
B) All pass filter
C) High pass filter
D) Low pass filter

Answer is D)

Explanation:The RC type Integrator is a type of Low Pass Filter.

16. Capacitor act as a _____________circuit at t =.∞ (Final Condition for inductor)

A) Open Circuit
B) Short Circuit
C) Grouded
D) Virtual

Answer is A)

At its final condition, a capacitor acts as an open circuit. This means that there is a break in the circuit.

17. Inductor act as a _____________circuit at t =.∞ (Final Condition for inductor)

A) Open Circuit
B) Short Circuit
C) Grounded
D) Virtual

Answer is B)

Explanation:At \(t=\infty \), an inductor acts as a short circuit. This is because the inductor has no voltage drop across it and no longer generates current.

18. At DC, capacitor acts as _________

A) Open Circuit
B) Short Circuit
C) Resistor
D) Inductor

Answer is A)

Explanation: Capacitive Reactance XC = 1/(2πfC) For DC, f=0 so, XC becomes infinite. Hence for dc, the capacitor acts as an open circuit.

19. In an RL series circuit, when the switch is closed and the circuit is complete, what is the response?

A) Response does not vary with time
B) Decays with time
C) Increases with time
D) First increases, then decrease

Answer is B)

Explanation: In an RL series circuit, the response decays with time because according to the equation, there is an exponential decrease in the response.

20. There are 6 branches and 2 essential nodes then how many equations are required to describe a circuit in the mesh-current method.

A) 3
B) 4
C) 5
D) 6

Answer is C)

Explanation: In Mesh-Current method, b-(n-1) equations are required to describe the circuit. b= the number of branches and n= the number of essential nodes. So, 6-(2-1) =5.

2. Which one of the following is called as a voltage controlled device

A) BJT
B) FET
C) DIODE
D) None of the above
Answer is B)
Whereas the bipolar transistor can be considered a current-controlled device (the current in the base), the field effect transistor is a voltage-controlled device.

3. Which of the following is true about Zener diode?

A) It is lightly doped.
B) It is mostly used in voltage regulator electronic circuits.
C) SIt is used in forward bias.
D) It has avalanche breakdown.
Answer is B)
Zener diode is a heavily doped diode. It is used in reverse bias. It has Zener breakdown. It is used in voltage regulators because it passes an excess amount of current in breakdown mode by maintaining constant voltage across the load..

4. α is the current gain of __________ configuration .

A) CB
B) CE
C) CC
D) CB and CC

Answer is A)

Alpha gain (α): In the common-base configuration, the current gain that is defined as the ratio of change in collector current to change in emitter current is known as alpha gain.

5. β is the current gain of __________ configuration.

A) CB
B) CE
C) CC
D) CB and CC

Answer is D)

Beta (β) is the current gain in the common emitter (CE) configuration of a transistor. It's defined as the ratio of the transistor's collector current to its base current: β =Ic/Ib.

6. In which region does BJT act as the OFF switch in electronic circuits?

A) Cut-Off
B) Saturation
C) Active
Reverse Saturation

Answer is B)

In the saturation region, the emitter-base junction is forward biased, the collector-base junction is also forward biased. This is the operating mode when no current flows through BJT.

7. Which of the following is true about the depletion layer channel in an NMOS electronic circuit?

A) Inverted change in the channel increases from source to drain
B) Inverted charge remain constant
C) Inverted change in the channel decreases from source to drain
D) Potential in the channel decreases from source to drain

Answer is C)

When the depletion layer starts moving into the channel, due to the reverse bias of drain and substrate voltage, the inverted charge in the channel decreases from source to drain..

8 Which of the following is the correct order of turn-off times?

A) MOSFET < BJT < IGBT < SCR
B) MOSFET < IGBT < BJT < SCR
C) SCR < BJT < IGBT < MOSFET
D) BJT < MOSFET < IGBT < SCR

Answer is A)

Explanation: Electronic devices like MOSFET have the lowest turn-off times (nanoseconds). BJT has turn-off times in between nanoseconds to microseconds. IGBT and SCR have turn-off times of about 1 and 5 microseconds respectively.

9.Avanche breakdown occurs when the reverse bais voltage above_______ volts.

A) 6 Volts
B) 8 Volts
C) 10 Volts
D) 12 Volts

Answer is B)

Avalanche breakdown occurs in a p-n junction when the reverse bias voltage (VBR) is greater than 8 volts.

10. UJT can be used as ________________________

A) saw tooth generator
B) regulator
C) rectifier
D) amplifier

Answer is C)

Explanation: It is widely used in the triggering circuits for silicon controlled rectifiers..

11. SCR turned off when ______

A) gate is reverse biased
B) gate removed
C) anode current reduced to zero
D) gate voltage reduced to zero

Answer is C)

Explanation:To turn OFF the conducting SCR, the anode or forward current of SCR must be reduced to zero.

12. SCR is a __________ device.

A) Uncontrolled
B) Semi-controlled
C) Fully controlled
D) Voltage

Answer is B)

Explanation:The SCR is a semi-controlled device. Turn-on time can be controlled by using a gate pulse but commutation circuit is required to turn off the device.

13. Depletion MOSFET can operate in ______

A) Depletion Mode Only
B) Enhancement Mode Only
C) Both
D) None of these

Answer is C)

Explanation: Depletion MOSFET can work in both depletion and enhancement mode.

14. A solar cell works on the principle of _________________ effect.

A) photo synthesis
B) photoelectric
C) photostatic
D) photovoltaic

Answer is D)

Explanation:Solar cell works on the principle of photovoltaic effect according to which free electrons are produced when light of certain wavelength is incident on semiconductors.

15. A solar cell converts :

A) Electrical energy into heat energy
B) Mechanical energy into electrical energy
C) Chemical energy into electrical energy
D) None of the above

Answer is D)

Explanation: A solar cell converts solar energy into electrical energy.

16. The control element of an SCR _______________

A) Gate
B) Drain
C) Source
D) All the above

Answer is A)

Explanation: Gate the control element in the Silicon Controlled Resistor. Gate is used to trigger the device into conduction by the application of a small voltage.

17. In the breakdown region, a zener diode behaves like a _______ source.

A) Constant voltage
B) Constant Current
C) Constant vResistance
D) All the above

Answer is A)

Explanation:In the breakdown region, a zener diode behaves like a constant voltage source..

18. A zener diode is destroyed if it ________.

A) Is forward biased
B) SIs reverse biased
C) Carries more than rated current
D) None of the above

Answer is C)

Explanation: A zener diode is destroyed if it Carries more than rated current.

19. A PN junction that radiates energy as light instead of as heat is called a_____

A) LED
B) Photo-diode
C) Photo-Cell
D) Zener Diode

Answer is A)

Explanation: A PN junction that radiates energy as light instead of as heat is called a LED

20. The transistor acts as an amplifier in the __________ region.

A) Cut-Off Region
B) Saturation Region
C) Breakdown Region
D) Active Region

Answer is D)

Explanation: Transistor acts as an amplifier in the active region of its output characteristics.

21. The capacitance of a varactor diode increases when reverse voltage across it

A) Decreases
B) Increases
C) Breaks down
D) Stores charge

Answer is A)

Explanation: The capacitance of a varactor diode increases when reverse voltage across it decreases.

22. The device associated with voltage controlled capacitance is a___

A) LED
B) Photo diode
C) Varactor diode
D) Zener diode

Answer is C)

Explanation: The device associated with voltage controlled capacitance is a Varactor diode

23. Photo Diode can be used in ______________________

A) Fiber Optic Receiver
B) Fiber Optic Transmiter
C) Both
D) None of these

Answer is C)

Explanation: photodiodes can be used in fiber optic receivers to convert weak light signals into electrical signals for processing information..

24.In case of enhancement n-channel MOSFETs ______

A) Vgs has negative polarity and Vds has positive polarity
B) Vgs has positive polarity and Vds has positive polarity
C) Vgs has positive polarity and Vds has negative polarity
D) Vgs has negative polarity and Vds has negative polarity

Answer is C)

Explanation: MOSFETs are commonly used as switches. For example, an enhancement-mode N-channel MOSFET can be used to switch a lamp on and off by adjusting the input gate voltage (Vgs) to a positive voltage to turn it on, and a negative voltage or zero to turn it off.

25. What is the main advantage of FET which makes it more useful in industrial applications?

A) Voltage controlled operation
B) Less cost
C) Small size
D) Semiconductor device

Answer is C)

Explanation: Because of its small size, the IC chips can be made even smaller which reduces the wear and tear. The process technology used with process technology constant a which is the ratio of Width and Length, the FET is made more advantageous.

26. BJT is a ___________________ controlled device.

A) Voltage Controlled Device
B) Temperature controlled Device
C) Pressure Controlled device
D) Current Controlled Device

Answer is D)

BJT's are current-driven devices i.e. It is a current-controlled device.

ELECTRONIC DEVICES AND CIRCUITS (EDC) MID - I PRACTICE QUESTIONS

ELECTRONIC DEVICES AND CIRCUITS - EDC

MID-I PRACTICE QUESTIONS

MULTIPLE CHOICE QUESTION AND ANSWERS

======================================================================

1. Which rectifier requires four diodes ___________.

A) Full Wave Rectifier
B) Half Wave Rectifier
C) Bridge Rectifier
D) Voltage Quadruple

Answer is C)

Explanation: A bridge rectifier is a type of rectifier that uses four diodes.

2. Efficiency of Half Wave Rectifier is ___________.

A) 81.2%
B) 8.12%
C) 40.6%
D) 4.06%

Answer is C)

Explanation: A half-wave rectifier's efficiency is 40.6%. This is lower than the efficiency of a full-wave rectifier, which is twice as much.

3. Efficiency of Full Wave Rectifier is_____________________.

A) 81.2%
B) 8.12%
C) 40.6%
D) 4.06%
Answer is A)
The efficiency of a full-wave rectifier is 81.2%. This is the ratio of the DC output power to the AC input power.

4. The breakdown mechanism in a lightly doped p-n junction under reverse biased condition is called.

A) Avalanche breakdown.
B) zener breakdown.
C) Breakdown by tunneling.
D) High voltage breakdown.

Answer is B)

Explanation: The breakdown mechanism in a lightly doped p-n junction under reverse biased condition is called Zener breakdown.

5.In a PN diode, for constant value of current at room temperature, dv/dt varies approximately at the rate of.

A) 25 mV/deg c
B) 2.5 mV/deg c
C) -25 mV/deg c
D) -2.5 mV/deg c

Answer is D)

Explanation: if the temperature is increased at fixed voltage, the current I increases. To bring the current I to the original value, the voltage V has to be reduced. It is found that at room temperature for either germanium or silicon, dv/dt = -2.5 mv/deg c.

6. ________ is a circuit which converts AC voltages and currents into pulsating DC voltages and currents.

A) A Rectifier
B) Inverter
C) Chopper
cycloconverter

Answer is A)

Explanation: A rectifier is an electrical device that converts alternating current (AC) into direct current (DC). The process of converting AC to DC is called rectification.

7. Ripple of a capacitive filter ____________ as load resistance increases.

A) Increases
B) Remains same
C) Decreases
D) None of the above

Answer is C)

Explanation: In a capacitive filter, the ripple voltage decreases as the load resistance increases. This is because the load resistance affects the filter capacitor's discharge time constant, which in turn affects the ripple voltage.

8 Relation between % efficiency and Transformer Utilization factor is given by _________

A) the expected current draw from the supply
B) how much ripple voltage is acceptable in the supply
C) Both A & B
D) None Of the above

Answer is C)

Explanation: The relation between percent efficiency and transformer utilization factor (TUF) is given by the expected current draw from the supply and how much ripple voltage is acceptable in the supply.

9. Peak inverse voltage of centre tapped full wave rectifier is _____________.

A) Vm
B) 2Vm
C) 3Vm
D) 0

Answer is B)

Explanation: The peak inverse voltage (PIV) of a center tapped full wave rectifier is 2Vmax, which is twice the transformer secondary terminal voltage.

10.A C-L-C filter is also known as __________ filter

A)“alpha” (α)
B) “Pi” (π).
C) “beta” (β).
D) “Delta” (Δ).

Answer is B)

Explanation: A C-L-C filter is also known as a pi filter or capacitor input filter. The C-L-C filter is an electronic filter circuit that consists of a series connection of a capacitor, an inductor, and another capacitor arranged in the shape of the Greek letter “Pi” (π).

11. The processes of adding impurities to semiconductor is called____________

A) Damping
B) Doping
C) Denting
D) Droppin

Answer is B)

The process of adding impurities to a semiconductor is called doping. The impurities are called dopants. Doping increases the electrical conductivity of a semiconductor.

12. PN junction failure above 8 V is caused predominantly due to _________

A) Avalanche Effect
B) Pintched Effect
C) Loading Effect
D) Non of the above

Answer is A)

A p-n junction that experiences breakdown above 5 volts is caused by the avalanche effect. The avalanche effect occurs when the reverse bias voltage applied to the diode is increased to a high enough value, causing the diode's PN junction to overheat and fail.

13. The BJT is a ______________ terminal device.

A) One
B) TWO
C) THREE
D) FOUR

Answer is C)

The BJT is a THREE terminal device.

14. The circuits used for getting the desired and proper operating point are known as ______

A) Alpha or A-point 
B) Doping or D-point 
C) Brew or B-point
D) Quiescent point or Q-point

Answer is D)

The operating point is a specific point within the operation characteristic of a technical device. It is also called as Quiescent point or Q-point.

15. A Rectifier is used to convert ___________________

A) AC to DC
B) DC to Ac
C) DC to DC
D) AC to AC

Answer is C)

A Rectifier is used to convert AC to DC

16. Higher value of ripple factor indicates _________

A) Hower AC Componet
B) Larger DC Componet
C) Larger AC Componets
D) Lower DC Componet

Answer is C)

A higher value of ripple factor indicates that the rectifier's output has a larger AC component. Ripple factor is a measure of the quality of an AC power supply, and is the ratio of the peak-to-peak ripple voltage to the DC input voltage. A higher ripple factor indicates a poorer quality of power supply.

17. The ripple factor of a Full-wave rectifier is _______________

A) 48.2%
B) 40.2%
C) 81.6%
D) 86.2%

Answer is A)

The ripple factor of a full-wave rectifier is 0.482, or 48.2%.

18.The ripple factor of a Half-wave rectifier is _______________

A) 0.21
B) 1.21
C) 2.21
D) 3.21

Answer is B)

The ripple factor of a half-wave rectifier is 1.21. The ripple factor is the ratio between the RMS value of the AC voltage (on the input side) and the DC voltage (on the output side) of the rectifier.

19. The Clipper is also called as_________________________

A) Bipass circuit
B) Regulated circuit
C) Slicer circuit
D) Limiter circuit

Answer is D)

Clipper circuits are the circuits that clip off or remove a portion of an input signal, without causing any distortion to the remaining part of the waveform. It is also known as the limiter circuit

20. The Clamper is also called as_________________________

A) Lever Shifter
B) Limiter Circuit
C) Regulated Circuit
D) None of the Above

Answer is B)

A clamper is also known as a clamping circuit, DC voltage restorer, IC restorer, and AC signal level shifter.

21. Diffusion current there will be movement from ___________________ concentration to ___________

A) Lower concentration to a higher concentration
B) higher concentration to a lower concentration
C) higher doping to a lower doping
D) lower doping to a higher doping

Answer is B)

Diffusion current is the movement of charge carriers from a higher concentration to a lower concentration.

22. Which rectifier has the least ratio of rectification _______________________

A) Half Wave rectifier
B) Full Wave Rectifier
C) Bridge Rectifier
D) None of the above

Answer is A)

Half-wave rectifiers are the simplest rectifiers and are less efficient than full-wave rectifiers. Half-wave rectifiers have a rectification efficiency of 40.6% and a ripple factor of 1.21,

23. The base-emitter junction in a bipolar junction transistor (BJT) is _______ biased, while the base-collector junction is ______ biased.

A) Reverse and Forward
B) Negatibe and Positive
C) Forward and Reverse
D) Positive and Negative

Answer is C)

The base-emitter junction in a bipolar junction transistor (BJT) is forward biased, while the base-collector junction is reverse biased.

24. Clippers circuits are used for_______________

A) prevent a signal from exceeding
B) prevent a signal from losing
C) prevent a signal from circuit damage
D) All of the above

Answer is A)

In electronics, a clipper is a circuit designed to prevent a signal from exceeding a predetermined reference voltage level

25. Diode clamper circuit used for

A) improving the reverse saturation time
B) improving the reverse damping time
C) improving the reverse recovery time
D) None of the above

Answer is C)

For improving the reverse recovery time, clampers are used.