9294 + Mcqs in Electronics and Communication Engineering Page 69 McqOptions

3401.	An RL series circuit has an impedance of 20 &ohm; when frequency is 25 Hz. At f= 50 Hz, the impedance will be
A.	40 &ohm;
B.	20 &ohm;
C.	less than 40 W but more than 20 &ohm;
D.	less than 20 W but more than 10 &ohm;
Answer» D. less than 20 W but more than 10 &ohm;

Discussion

3402.	In figure, the voltmeter is ideal. The transformer has two identical windings with perfect coupling. The reading of voltmeter is
A.	440 V
B.	220 V
C.	110 V
D.	zero
Answer» E.

Discussion

3403.	The resistance of the circuit shown is figure is
A.	5 &ohm;
B.	More than 6 &ohm;
C.	More than 4 &ohm;
D.	Between 6 and 7 &ohm;
Answer» B. More than 6 &ohm;

Discussion

3404.	The final value of is
A.
B.	2
C.	1
D.	zero
Answer» D. zero

Discussion

3405.	S is open for a long time and steady state is reached S is closed at t = 0. Let iL the current in the inductor At t = 0+, is given by
A.	-2
B.	-1
C.	-4
D.	-
Answer» C. -4

Discussion

3406.	The self inductances of two coils are 27 H and 3 H. If the winding or coils is such that 50% of flux of one links the other, the mutual inductance is
A.	30 H
B.	24 H
C.	9 H
D.	4.5 H
Answer» E.

Discussion

3407.	In a lead acid cell, the positive plate has spongy lead.
A.	True
B.	False
Answer» C.

Discussion

3408.	For H(s) to be positive real, the condition Re[H(j )] 0 for 0 is
A.	a necessary condition
B.	a sufficient condition
C.	a necessary and sufficient condition
D.	is not a necessary condition
Answer» B. a sufficient condition

Discussion

3409.	In the circuit, shown the current I marked is given by
A.	2.22 A
B.	1.78 A
C.	4.44 A
D.	2 A
Answer» B. 1.78 A

Discussion

3410.	In the circuit of figure, the power consumed in resistance R is measured when one source is acting at one time. These values are 18 W, 50 W and 98 W. When all source act together the maximum and minimum power can be
A.	98 W and 18 W
B.	166 W and 18 W
C.	450 W and 2 W
D.	166 W and 2 W
Answer» C. 450 W and 2 W

Discussion

3411.	The resistance RAB in the circuit is
A.	10 &ohm;
B.	12 &ohm;
C.	9 &ohm;
D.	3 &ohm;
Answer» D. 3 &ohm;

Discussion

3412.	In the circuit of figure the current through L at t = is
A.	0 A
B.	10 A
C.	6.67 A
D.	5.1 A
Answer» C. 6.67 A

Discussion

3413.	The current source in figure, can be replaced by
A.	a voltage source of 20 V in series with 5 ohm resistance
B.	a voltage source of 16 V in series with 4 ohm resistance
C.	a voltage source of 20 V in series with 4 &ohm; resistance
D.	a voltage source of 16 V in series with 5 &ohm; resistance
Answer» C. a voltage source of 20 V in series with 4 &ohm; resistance

Discussion

3414.	If the voltage across the last resistor is V, and all the resistor is unity. Then Vs is given by
A.	8 V
B.	4 V
C.	13 V
D.	0
Answer» B. 4 V

Discussion

3415.	In figure, iL at t = 0+ is
A.	0
B.	I
C.	infinite
D.	<img src="/_files/images/electronics-and-communication-engineering/networks-analysis-and-synthesis/102-344-1.png">
Answer» B. I

Discussion

3416.	In a purely inductive circuit, the current __________ the voltage by __________ .
A.	lags, 0
B.	leads, 90
C.	lags, 90
D.	lags, 45
Answer» D. lags, 45

Discussion

3417.	In figure, capacitor is uncharged. The switch is closed at t = 0 at t = 0+ di/dt is
A.	100 A/s
B.	-100 A/s
C.	1000 A/s
D.	-1000 A/s
Answer» C. 1000 A/s

Discussion

3418.	In figure, the current iL at t = is
A.	I
B.	0
C.	<img src="/_files/images/electronics-and-communication-engineering/networks-analysis-and-synthesis/102-346-1.png">
D.	<img src="/_files/images/electronics-and-communication-engineering/networks-analysis-and-synthesis/102-346-2.png">
Answer» B. 0

Discussion

3419.	A resistance coil has self inductance L, resistance R and capacitance C. The impedance across the coil is
A.	<img src="/_files/images/electronics-and-communication-engineering/networks-analysis-and-synthesis/118-635-1.png">
B.	<img src="/_files/images/electronics-and-communication-engineering/networks-analysis-and-synthesis/118-635-2.png">
C.	<img src="/_files/images/electronics-and-communication-engineering/networks-analysis-and-synthesis/118-635-3.png">
D.	<img src="/_files/images/electronics-and-communication-engineering/networks-analysis-and-synthesis/118-635-4.png">
Answer» C. <img src="/_files/images/electronics-and-communication-engineering/networks-analysis-and-synthesis/118-635-3.png">

Discussion

3420.	Assertion (A): The response of a network to unit impulse can be obtained directly from the network function.Reason (R): The response of a network for any input can be obtained from impulse response.
A.	Both A and R are true and R is correct explanation of A
B.	Both A and R are true and R is not the correct explanation of A
C.	A is true but R is false
D.	A is false but R is true
Answer» B. Both A and R are true and R is not the correct explanation of A

Discussion

3421.	When a lead acid cell is in fully charged condition the positive and negative plates are similar.
A.	True
B.	False
Answer» C.

Discussion

3422.	Two capacitors of 1 F and 2 F capacitance are connected in parallel across a 30 V dc battery. After the capacitors have been charged, the charges across the two capacitors will be
A.	30 C each
B.	60 C each
C.	30 C and 60 C respectively
D.	60 C and 30 C respectively
Answer» D. 60 C and 30 C respectively

Discussion

3423.	If A = 4 7 , A2 is
A.	16 14
B.	16 49
C.	16 7
D.	16 3.5
Answer» B. 16 49

Discussion

3424.	A constant k high pass p section has a characteristic impedance of 300 &ohm; at f = . At f = fc, the characteristic impedance will be
A.	zero
B.
C.	300 &ohm;
D.	more than 300 &ohm;
Answer» C. 300 &ohm;

Discussion

3425.	For the three coupled coils shown in figure, KVL equation is
A.	<img src="/_files/images/electronics-and-communication-engineering/networks-analysis-and-synthesis/105-405-2.png">
B.	<img src="/_files/images/electronics-and-communication-engineering/networks-analysis-and-synthesis/105-405-3.png">
C.	<img src="/_files/images/electronics-and-communication-engineering/networks-analysis-and-synthesis/105-405-4.png">
D.	<img src="/_files/images/electronics-and-communication-engineering/networks-analysis-and-synthesis/105-405-5.png">
Answer» D. <img src="/_files/images/electronics-and-communication-engineering/networks-analysis-and-synthesis/105-405-5.png">

Discussion

3426.	Zinc oxide is a non-linear resistance.
A.	True
B.	False
Answer» B. False

Discussion

3427.	Assertion (A): The inductance of an iron cored solenoid is not constant.Reason (R): BH curve of an iron specimen is non-linear.
A.	Both A and R are true and R is correct explanation of A
B.	Both A and R are true and R is not the correct explanation of A
C.	A is true but R is false
D.	A is false but R is true
Answer» B. Both A and R are true and R is not the correct explanation of A

Discussion

3428.	Figure shows a dc circuit. The Thevenin's equivalent circuit at terminals a - b is
A.	<img src="/_files/images/electronics-and-communication-engineering/networks-analysis-and-synthesis/116-609-2.png">
B.	<img src="/_files/images/electronics-and-communication-engineering/networks-analysis-and-synthesis/116-609-3.png">
C.	<img src="/_files/images/electronics-and-communication-engineering/networks-analysis-and-synthesis/116-609-4.png">
D.	not feasible
Answer» E.

Discussion

3429.	The dependent current source shown in given figure.
A.	delivers 80W
B.	absorbs 80W
C.	deliver 40W
D.	absorbs 40W
Answer» C. deliver 40W

Discussion

3430.	In an RL series circuit the inductance is 1H and current at an instant is 0.6 A. The energy stored in magnetic field is
A.	0.36 J
B.	0.18 J
C.	0.09 J
D.	0.03 J
Answer» C. 0.09 J

Discussion

3431.	In a series ac circuit a voltage of 20 V at 25 Hz causes a current of 0.20 A, while the same voltage at 75 Hz causes a current of 0.12 A. The circuit consists of
A.	R and C in parallel
B.	R and C in series
C.	R and L in series
D.	either (a) or (b)
Answer» C. R and L in series

Discussion

3432.	In a practical voltage source, the terminal voltage
A.	cannot be less than source voltage
B.	cannot be higher than source voltage
C.	is always less than source voltage
D.	is always equal to source voltage
Answer» C. is always less than source voltage

Discussion

3433.	When slider of the potentiometer AB is in the position shown in figure, what resistance reading would be indicated by an ohmmeter connected between A and C?
A.	zero
B.	infinite
C.	can't say
D.	none of the above
Answer» B. infinite

Discussion

3434.	In figure, the value of R should be
A.	12 &ohm;
B.	6 &ohm;
C.	3 &ohm;
D.	1.5 &ohm;
Answer» C. 3 &ohm;

Discussion

3435.	An RLC series circuit has R = 7.07 &ohm;, L = .707 H and C = 7.07 F. At Half power frequencies the circuit impedance is likely to be
A.	7.07 &ohm;
B.	10 &ohm;
C.	14.14 &ohm;
D.	20 &ohm;
Answer» C. 14.14 &ohm;

Discussion

3436.	In a series R, L, C circuit the impedance triangle is the same when XL < XC and XL > XC .
A.	True
B.	False
Answer» C.

Discussion

3437.	The zinc can of a dry cell serves as positive terminal.
A.	True
B.	False
Answer» C.

Discussion

3438.	A dielectric does not have leakage current.
A.	True
B.	False
Answer» C.

Discussion

3439.	A series RLC circuit has a resonant frequency of 1000 Hz. The maximum voltage across C is likely to occur at a frequency of about
A.	1000 Hz
B.	2000 Hz
C.	1025 Hz
D.	975 Hz
Answer» E.

Discussion

3440.	A clock signal coordinates the working of different flip flops.
A.	True
B.	False
Answer» B. False

Discussion

3441.	In 8085, usually the vector location and the next two memory location contain a JMP instruction. This allows the programs to branch to
A.	a longer subroutine
B.	a shorter subroutine
C.	a subroutine free path
D.	none of the above
Answer» B. a shorter subroutine

Discussion

3442.	In which of these does thermionic emission occur?
A.	LED
B.	LCD
C.	VF display
D.	None
Answer» D. None

Discussion

3443.	The basic circuit configuration for TTL resembles that of a
A.	AND gate
B.	NAND gate
C.	NOR gate
D.	OR gate
Answer» C. NOR gate

Discussion

3444.	Time delay of a TTL standard family is about
A.	180 ns
B.	50 ns
C.	18 ns
D.	3 ns
Answer» D. 3 ns

Discussion

3445.	Assertion (A): Boolean expressions can be easily simplified using Karnaugh map.Reason (R): Karnaugh map can be drawn for minterms as well as max terms.
A.	Both A and R are correct and R is correct explanation of A
B.	Both A and R are correct but R is not correct explanation of A
C.	A is true, R is false
D.	A is false, R is true
Answer» C. A is true, R is false

Discussion

3446.	The circuit shown in figure converts
A.	BCD to binary code
B.	binary to excess-3 code
C.	excess-3 to Gray code
D.	gray to binary code
Answer» E.

Discussion

3447.	Out of multiplexer and demultiplexer, which has select inputs?
A.	Multiplexer only
B.	Demultiplexer only
C.	Both multiplexer and demultiplexer
D.	None
Answer» D. None

Discussion

3448.	K maps can be drawn
A.	only for 2 variables
B.	only for 3 variables
C.	only for 4 variables
D.	for any number of variables
Answer» E.

Discussion

3449.	Direct-memory-access channel facilitates data to move into and out of the system.
A.	without subroutine
B.	with equal time delay
C.	without programme intervention
D.	on first come first serve basis
Answer» D. on first come first serve basis

Discussion

3450.	For emitter-couple logic, the switching speed is very high because
A.	negative logic is used
B.	the transistors are not saturated when conducting
C.	emitter-coupled transistors are used
D.	multi-emitter transistors are used
Answer» C. emitter-coupled transistors are used

Discussion

Explore topic-wise MCQs in Engineering.

An RL series circuit has an impedance of 20 &amp;ohm; when frequency is 25 Hz. At f= 50 Hz, the impedance will be

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Figure shows a dc circuit. The Thevenin's equivalent circuit at terminals a - b is

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In a practical voltage source, the terminal voltage

When slider of the potentiometer AB is in the position shown in figure, what resistance reading would be indicated by an ohmmeter connected between A and C?

In figure, the value of R should be

An RLC series circuit has R = 7.07 &amp;ohm;, L = .707 H and C = 7.07 F. At Half power frequencies the circuit impedance is likely to be

In a series R, L, C circuit the impedance triangle is the same when XL &lt; XC and XL &gt; XC .

The zinc can of a dry cell serves as positive terminal.

A dielectric does not have leakage current.

A series RLC circuit has a resonant frequency of 1000 Hz. The maximum voltage across C is likely to occur at a frequency of about

A clock signal coordinates the working of different flip flops.

In 8085, usually the vector location and the next two memory location contain a JMP instruction. This allows the programs to branch to

In which of these does thermionic emission occur?

The basic circuit configuration for TTL resembles that of a

Time delay of a TTL standard family is about

Assertion (A): Boolean expressions can be easily simplified using Karnaugh map.Reason (R): Karnaugh map can be drawn for minterms as well as max terms.

The circuit shown in figure converts

Out of multiplexer and demultiplexer, which has select inputs?

K maps can be drawn

Direct-memory-access channel facilitates data to move into and out of the system.

For emitter-couple logic, the switching speed is very high because

An RL series circuit has an impedance of 20 &ohm; when frequency is 25 Hz. At f= 50 Hz, the impedance will be

In a purely inductive circuit, the current the voltage by .

A constant k high pass p section has a characteristic impedance of 300 &ohm; at f = . At f = fc, the characteristic impedance will be

An RLC series circuit has R = 7.07 &ohm;, L = .707 H and C = 7.07 F. At Half power frequencies the circuit impedance is likely to be

In a series R, L, C circuit the impedance triangle is the same when XL < XC and XL > XC .