9294 + Mcqs in Electronics and Communication Engineering Page 9 McqOptions

401.	At room temperature, the current in intrinsic semiconductor is due to
A.	holes
B.	electrons
C.	ions
D.	holes and electrons
Answer» E.

Discussion

402.	A sinusoidal voltage has peak to peak value of 100 V. The rms value is
A.	50 V
B.	70.7 V
C.	35.35 V
D.	141.41 V
Answer» D. 141.41 V

Discussion

403.	The current wave shape shown in figure (1) is applied to a circuit element. The voltage across the element is shown in figure (2). The element is
A.	R
B.	L
C.	C
D.	Semiconductor
Answer» D. Semiconductor

Discussion

404.	In figure, the current supplied by battery immediately after switching on the circuit is
A.	1 A
B.	4 A
C.	10 A
D.	0
Answer» B. 4 A

Discussion

405.	The time constant of the circuit in figure shown.
A.	RC
B.	<img src="/_files/images/electronics-and-communication-engineering/networks-analysis-and-synthesis/131-819-2.png">
C.	<img src="/_files/images/electronics-and-communication-engineering/networks-analysis-and-synthesis/131-819-3.png">
D.	<img src="/_files/images/electronics-and-communication-engineering/networks-analysis-and-synthesis/131-819-4.png">
Answer» C. <img src="/_files/images/electronics-and-communication-engineering/networks-analysis-and-synthesis/131-819-3.png">

Discussion

406.	A two branch parallel circuit has a 20 &ohm; resistance and 1 H inductance in one branch and a 100 F capacitor in the second branch. It is fed from 100 V ac supply, at resonance, the input impedance of the circuit is
A.	500 &ohm;
B.	50 &ohm;
C.	20 &ohm;
D.	5 &ohm;
Answer» B. 50 &ohm;

Discussion

407.	In the circuit shown in given figure, the values of i(0+) and I( ), will be respectively
A.	zero and 1.5 A
B.	1.5 A and 3 A
C.	3 A and zero
D.	3 A and 1.5 A
Answer» D. 3 A and 1.5 A

Discussion

408.	The impedance matrices of two, two-port network are given by and . If these two networks are connected in series, the impedance matrix of the resulting two-port network will be
A.	<img src="/_files/images/electronics-and-communication-engineering/networks-analysis-and-synthesis/144-1006-3.png">
B.	<img src="/_files/images/electronics-and-communication-engineering/networks-analysis-and-synthesis/144-1006-4.png">
C.	<img src="/_files/images/electronics-and-communication-engineering/networks-analysis-and-synthesis/144-1006-5.png">
D.	indeterminate
Answer» C. <img src="/_files/images/electronics-and-communication-engineering/networks-analysis-and-synthesis/144-1006-5.png">

Discussion

409.	As compared to the number of network elements in Brune synthesis, the number of network elements Bott-and Duffin in realization is
A.	more
B.	less
C.	equal
D.	any of the above
Answer» B. less

Discussion

410.	The electrical energy required to heat a bucket of water to a certain temperature is 2 kWh. If heat losses, are 25%, the energy input is
A.	2.67 kWh
B.	3 kWh
C.	2.5 kWh
D.	3.5 kWh
Answer» B. 3 kWh

Discussion

411.	The circuit in figure will act as ideal current source with respect to terminals A and B when frequency is
A.	0
B.	1 rad/sec
C.	4 rad/sec
D.	16 rad/sec
Answer» C. 4 rad/sec

Discussion

412.	The current rating of a cable depends on
A.	length of cable
B.	diameter of cable
C.	both length and diameter of cable
D.	none of the above
Answer» C. both length and diameter of cable

Discussion

413.	In an ac circuit, the maximum and minimum values of power factor can be
A.	2 and 0
B.	1 and 0
C.	0 and -1
D.	1 and -1
Answer» C. 0 and -1

Discussion

414.	In the series circuit shown in figure, for series resonance, the value of the coupling coefficient, K will be
A.	0.25
B.	0.5
C.	0.1
D.	1
Answer» B. 0.5

Discussion

415.	Which of the following pairs are correctly matched? Brune's realisation : realisation with ideal transformer.Cauer realisation : ladder realisation.Bott Duffin realisation : with non ideal transformer. Select the answer using the following codes:
A.	1, 2 and 3
B.	2 and 3
C.	1 and 3
D.	1 and 2
Answer» E.

Discussion

416.	In the figure shown, A1, A2, A3 are identical Ammeters. If A1 and A3 read 5 and 13 A respectively, reading of A2 will be
A.	8
B.	13 A
C.	18
D.	12 A
Answer» E.

Discussion

417.	The synthesis of minimum function was suggested by
A.	O'Brune
B.	R. Richards
C.	Bott and Duffin
D.	none of the above
Answer» B. R. Richards

Discussion

418.	A 0.5 F capacitor is connected across a 10 V battery. After a long time, the circuit current and voltage across capacitor will be
A.	0.5 A and 0 V
B.	0 A and 10 V
C.	20 A and 5 V
D.	0.05 A and 5 V
Answer» C. 20 A and 5 V

Discussion

419.	Wave A = 100 sin t and wave B = 100 cos t. Then
A.	rms values of the two waves are equal
B.	rms values of A is more than that of B
C.	rms values of A is less than that of B
D.	rms values of the two waves may or may not be equal
Answer» B. rms values of A is more than that of B

Discussion

420.	A capacitor stores 0.15C at 5 V. Its capacitance is
A.	0.75 F
B.	0.75 F
C.	0.03 F
D.	0.03 F
Answer» D. 0.03 F

Discussion

421.	For node 1 in figure, KCL equation is
A.	<img src="/_files/images/electronics-and-communication-engineering/networks-analysis-and-synthesis/107-448-2.png">
B.	<img src="/_files/images/electronics-and-communication-engineering/networks-analysis-and-synthesis/107-448-3.png">
C.	<img src="/_files/images/electronics-and-communication-engineering/networks-analysis-and-synthesis/107-448-4.png">
D.	none of the above
Answer» D. none of the above

Discussion

422.	In the circuit of figure, the switch is closed at t = 0. At t = 0+ the current through C is
A.	4 A
B.	2.5 A
C.	3.1 A
D.	0
Answer» B. 2.5 A

Discussion

423.	The drift velocity of electrons is
A.	very small as compared to speed of light
B.	equal to speed of light
C.	almost equal to speed of light
D.	half the speed of light
Answer» B. equal to speed of light

Discussion

424.	Z(c) for the network shown in the figure is The value of C and R are, respectively
A.	1/6 F and 4 &ohm;
B.	2/9 F and 9/2 &ohm;
C.	2/3 F and 1/2 &ohm;
D.	1/2 F and 1 &ohm;
Answer» B. 2/9 F and 9/2 &ohm;

Discussion

425.	The degree of the nodes 1, 2, 3, 4 is
A.	2
B.	3
C.	2 for 1, 2, 3, and 3 for 4
D.	all 3
Answer» E.

Discussion

426.	In an RC series circuit R = 100 &ohm; and XC = 10 &ohm;. In this circuit
A.	the current and voltage are in phase
B.	the current leads the voltage by about 6
C.	the current leads the voltage by about 84
D.	the current lags the voltage by about 6
Answer» C. the current leads the voltage by about 84

Discussion

427.	The impedance of an RC series circuit is 12 &ohm; at f= 50 Hz. At f= 200 Hz, the impedance will be
A.	more than 12
B.	less than 3
C.	more than 3 &ohm; but less than 12 &ohm;
D.	more than 12 &ohm; but less than 24 &ohm;
Answer» D. more than 12 &ohm; but less than 24 &ohm;

Discussion

428.	Which of the following is correct for a driving point functions?
A.	The real parts of all poles must be negative
B.	The real parts of all poles and zeros must be negative
C.	The real parts of all poles and zeros must be negative or zero
D.	The real parts of all zeros must be negative
Answer» D. The real parts of all zeros must be negative

Discussion

429.	An infinite ladder is constructed with 1 &ohm; and 2 &ohm; resistors shown below.
A.	8.18 A
B.	0 A
C.	9 A
D.	can't determined
Answer» D. can't determined

Discussion

430.	A current is flowing through a conductor with non-uniform area of cross-section. Then
A.	current will be different at different cross-sections.
B.	current will be the same at all the cross-sections.
C.	current will be different but current density will be same at all the cross-sections
D.	current will be the same but current density will be different at different cross-sections.
Answer» E.

Discussion

431.	C = (2) (energy)/V2
A.	True
B.	False
Answer» B. False

Discussion

432.	In the circuit of figure the voltage across capacitor when switch is closed at t = is
A.	0 V
B.	20 V
C.	very large
D.	7.5 V
Answer» E.

Discussion

433.	Assertion (A): Power loss in a conductor of resistance P = I2R.Reason (R): When a conductor is carrying current with current density J as a result of applied field E, then heat developed/m3/ second = JE.
A.	Both A and R are true and R is correct explanation of A
B.	Both A and R are true but R is not 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 but R is not correct explanation of A

Discussion

434.	Assertion (A): For Diamond, r = 1Reason (R): Diamond is a diamagnetic material.
A.	Both A and R are true and R is correct explanation of A
B.	Both A and R are true but R is not 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 but R is not correct explanation of A

Discussion

435.	The hysteresis phenomenon in ferromagnetic materials exists at all temperatures.
A.	True
B.	False
Answer» C.

Discussion

436.	Assertion (A): Magnetic susceptibility of diamagnetic materials is much less than that of paramagnetic materials.Reason (R): For diamagnetic as well as paramagnetic materials, r is nearly equal to 1.
A.	Both A and R are true and R is correct explanation of A
B.	Both A and R are true but R is not 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 but R is not correct explanation of A

Discussion

437.	If a sample of germanium and a sample of silicon have the same impurity density and are kept at room temperature
A.	both will have equal value of resistivity
B.	both will have equal negative resistivity
C.	resistivity of germanium will be higher than that of silicon
D.	resistivity of silicon will be higher than that of germanium
Answer» E.

Discussion

438.	In metals the valence electron wave functions are strongly perturbed by the presence of neighbouring atoms.
A.	True
B.	False
Answer» B. False

Discussion

439.	Assertion (A): At a temperature of 1000 K, thermionic emission current is about 0.1 A/cm2 of surface.Reason (R): Thermionic emission current is given by Ith = SA0 T2 e-Ew/kT.
A.	Both A and R are true and R is correct explanation of A
B.	Both A and R are true but R is not 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 but R is not correct explanation of A

Discussion

440.	For a paramagnetic material, susceptiblity increases with increasing temperature.
A.	True
B.	False
Answer» C.

Discussion

441.	Hydrogen is used in
A.	large size transformers
B.	MCB
C.	large size generators
D.	circuit breakers
Answer» D. circuit breakers

Discussion

442.	If e is the charge of an electron, R is the radius of its orbit and is the angular velocity of electron, the magnetic dipole moment m of the orbit is \| m\| = e R2.
A.	True
B.	False
Answer» C.

Discussion

443.	The attraction between the nucleus and valence electron of copper atom is
A.	zero
B.	weak
C.	strong
D.	either zero or strong
Answer» C. strong

Discussion

444.	If the temperature of an extrinsic semiconductor is increased so that the intrinsic carrier concentration is doubled, then
A.	the majority carrier density is doubled
B.	the minority carrier density is doubled
C.	the minority carrier density becomes 4 times the original value
D.	both the majority and minority carrier densities double
Answer» E.

Discussion

445.	There is no hysteresis phenomenon is any dielectric material.
A.	True
B.	False
Answer» C.

Discussion

446.	A semi converter operates in two quadrants.
A.	True
B.	False
Answer» C.

Discussion

447.	The number of leads in an SCR are :
A.	2
B.	3
C.	4
D.	5
Answer» C. 4

Discussion

448.	Figure shows a chopper feeding RLE load, The free wheeling diode conducts when
A.	thyristor is on
B.	thyristor is off
C.	both when thyristor is on and thyristor is off
D.	partly when thyristor is off and partly when thyristor is on
Answer» C. both when thyristor is on and thyristor is off

Discussion

449.	The total number of leads in reverse conducting thyristor is
A.	2
B.	3
C.	1
D.	4
Answer» C. 1

Discussion

450.	In a thyristor the gate current is increased, then
A.	anode current will increase
B.	anode current will decrease
C.	anode current will remain constant
D.	anode current may increase or decrease
Answer» D. anode current may increase or decrease

Discussion

Explore topic-wise MCQs in Engineering.

At room temperature, the current in intrinsic semiconductor is due to

A sinusoidal voltage has peak to peak value of 100 V. The rms value is

The current wave shape shown in figure (1) is applied to a circuit element. The voltage across the element is shown in figure (2). The element is

In figure, the current supplied by battery immediately after switching on the circuit is

The time constant of the circuit in figure shown.

A two branch parallel circuit has a 20 &amp;ohm; resistance and 1 H inductance in one branch and a 100 F capacitor in the second branch. It is fed from 100 V ac supply, at resonance, the input impedance of the circuit is

In the circuit shown in given figure, the values of i(0+) and I( ), will be respectively

The impedance matrices of two, two-port network are given by and . If these two networks are connected in series, the impedance matrix of the resulting two-port network will be

As compared to the number of network elements in Brune synthesis, the number of network elements Bott-and Duffin in realization is

The electrical energy required to heat a bucket of water to a certain temperature is 2 kWh. If heat losses, are 25%, the energy input is

The circuit in figure will act as ideal current source with respect to terminals A and B when frequency is

The current rating of a cable depends on

In an ac circuit, the maximum and minimum values of power factor can be

In the series circuit shown in figure, for series resonance, the value of the coupling coefficient, K will be

Which of the following pairs are correctly matched? Brune's realisation : realisation with ideal transformer.Cauer realisation : ladder realisation.Bott Duffin realisation : with non ideal transformer. Select the answer using the following codes:

In the figure shown, A1, A2, A3 are identical Ammeters. If A1 and A3 read 5 and 13 A respectively, reading of A2 will be

The synthesis of minimum function was suggested by

A 0.5 F capacitor is connected across a 10 V battery. After a long time, the circuit current and voltage across capacitor will be

Wave A = 100 sin t and wave B = 100 cos t. Then

A capacitor stores 0.15C at 5 V. Its capacitance is

For node 1 in figure, KCL equation is

In the circuit of figure, the switch is closed at t = 0. At t = 0+ the current through C is

The drift velocity of electrons is

Z(c) for the network shown in the figure is The value of C and R are, respectively

The degree of the nodes 1, 2, 3, 4 is

In an RC series circuit R = 100 &amp;ohm; and XC = 10 &amp;ohm;. In this circuit

The impedance of an RC series circuit is 12 &amp;ohm; at f= 50 Hz. At f= 200 Hz, the impedance will be

Which of the following is correct for a driving point functions?

An infinite ladder is constructed with 1 &amp;ohm; and 2 &amp;ohm; resistors shown below.

A current is flowing through a conductor with non-uniform area of cross-section. Then

C = (2) (energy)/V2

In the circuit of figure the voltage across capacitor when switch is closed at t = is

Assertion (A): Power loss in a conductor of resistance P = I2R.Reason (R): When a conductor is carrying current with current density J as a result of applied field E, then heat developed/m3/ second = JE.

Assertion (A): For Diamond, r = 1Reason (R): Diamond is a diamagnetic material.

The hysteresis phenomenon in ferromagnetic materials exists at all temperatures.

Assertion (A): Magnetic susceptibility of diamagnetic materials is much less than that of paramagnetic materials.Reason (R): For diamagnetic as well as paramagnetic materials, r is nearly equal to 1.

If a sample of germanium and a sample of silicon have the same impurity density and are kept at room temperature

In metals the valence electron wave functions are strongly perturbed by the presence of neighbouring atoms.

Assertion (A): At a temperature of 1000 K, thermionic emission current is about 0.1 A/cm2 of surface.Reason (R): Thermionic emission current is given by Ith = SA0 T2 e-Ew/kT.

For a paramagnetic material, susceptiblity increases with increasing temperature.

Hydrogen is used in

If e is the charge of an electron, R is the radius of its orbit and is the angular velocity of electron, the magnetic dipole moment m of the orbit is | m| = e R2.

The attraction between the nucleus and valence electron of copper atom is

If the temperature of an extrinsic semiconductor is increased so that the intrinsic carrier concentration is doubled, then

There is no hysteresis phenomenon is any dielectric material.

A semi converter operates in two quadrants.

The number of leads in an SCR are :

Figure shows a chopper feeding RLE load, The free wheeling diode conducts when

The total number of leads in reverse conducting thyristor is

In a thyristor the gate current is increased, then

A two branch parallel circuit has a 20 &ohm; resistance and 1 H inductance in one branch and a 100 F capacitor in the second branch. It is fed from 100 V ac supply, at resonance, the input impedance of the circuit is

In an RC series circuit R = 100 &ohm; and XC = 10 &ohm;. In this circuit

The impedance of an RC series circuit is 12 &ohm; at f= 50 Hz. At f= 200 Hz, the impedance will be

An infinite ladder is constructed with 1 &ohm; and 2 &ohm; resistors shown below.