100525 + Interview Questions in GENERAL QA IN GENERAL AWARENESS Page 462 InterviewSolution

23051.	What is the commercial unit of electric energy? Convert it into joules.
Answer» Kilowatt hour – commercial unit of electrical energy. 1 kWh = 1000 Wh = 1000 J/S × 3600 sec = 3600000 J = 3.6 × 10⁶J

Discussion

23052.	Out of 60 W and 40 W lamps which one has higher electrical resistance when in use?
Answer» For the same applied voltage P & \(\frac{1}{R}\) i.e., less the same power of electrical device higher it is electrical resistance.

23052.

Out of 60 W and 40 W lamps which one has higher electrical resistance when in use?

Answer»

For the same applied voltage P & \(\frac{1}{R}\)

i.e., less the same power of electrical device higher it is electrical resistance.

Discussion

23053.	Write two points of difference between electric energy and electric power.
Answer» The work done or energy supplied by the source in maintaining the flow of electric current is called electrical energy. It appears in the from of heat given by H = VIt = \(\frac{v^2t}{R}\) = I²RT (i) It is equal to be product of power and time E = P × t (ii) It SI unit is joule (J) 1J = 1W × 1S Electric power: The time rate at which electronic energy is consumed or dissipated by an electrical device is called electric power and is given by P = VI = \(\frac{v^2}{R}\) = I²R It is equal to the rate of doing work by an energy source P = \(\frac{W}{t}\) Its SI unit is watt(W) 1W = 1 JS^-1

23053.

Write two points of difference between electric energy and electric power.

Answer»

The work done or energy supplied by the source in maintaining the flow of electric current is called electrical energy. It appears in the from of heat given by
H = VIt = \(\frac{v^2t}{R}\) = I²RT

(i) It is equal to be product of power and time E = P × t

(ii) It SI unit is joule (J)
1J = 1W × 1S

Electric power:
The time rate at which electronic energy is consumed or dissipated by an electrical device is called electric power and is given by
P = VI = \(\frac{v^2}{R}\) = I²R
It is equal to the rate of doing work by an energy source
P = \(\frac{W}{t}\)
Its SI unit is watt(W)
1W = 1 JS^-1

Discussion

23054.	What is meant by electric current? Name and define its SI unit. In a conductor electrons are flowing from B to A. What is the direction of conventional current? Give justification for your answer.
Answer» A steady current of 1 ampere flows through a conductor. Calculate the number of electrons that flows through any section of the conductor is 1 second (charge on electron 1.6 x 10¹⁹ Coulomb) Electric current: The amount of charge Q flowing through a particular area of cross section in unit time ‘t’ is called electric current, i.e., Electric current, I = Q/t SI unit of electric current is ampere One ampere of current is that current which flow when one coulomb of electric charge flowing through a particular area of cross section of the conductor is one second, i.e, 1A = 1 CS^-1 The direction of conventional current is A to B, i.e., opposite to the direction of flow of electrons. In a metal, flow of electrons carrying negative charge constitutes the current. Direction of flow of electrons given the direction of electronic current by convention, the direction of flow of positive charge is taken as the direction of conventional current charge = q = ne For q = I Coulomb \(\frac{1C}{1.6\times 10^{-19}C}\) = \(\frac{10^{19}}{1.6}\) = 6.25 x 10¹⁸ electrons

23054.

What is meant by electric current? Name and define its SI unit. In a conductor electrons are flowing from B to A. What is the direction of conventional current? Give justification for your answer.

Answer»

A steady current of 1 ampere flows through a conductor. Calculate the number of electrons that flows through any section of the conductor is 1 second (charge on electron 1.6 x 10¹⁹ Coulomb)

Electric current: The amount of charge Q flowing through a particular area of cross section in unit time ‘t’ is called electric current, i.e., Electric current, I = Q/t
SI unit of electric current is ampere

One ampere of current is that current which flow when one coulomb of electric charge flowing through a particular area of cross section of the conductor is one second, i.e, 1A = 1 CS^-1

The direction of conventional current is A to B, i.e., opposite to the direction of flow of electrons. In a metal, flow of electrons carrying negative charge constitutes the current. Direction of flow of electrons given the direction of electronic current by convention, the direction of flow of positive charge is taken as the direction of conventional current charge
= q = ne
For q = I Coulomb

\(\frac{1C}{1.6\times 10^{-19}C}\) = \(\frac{10^{19}}{1.6}\) = 6.25 x 10¹⁸ electrons

Discussion

23055.	An isolated particle of mass `m` is moving in horizontal plane` xy` along the `x`-axis, at a certain height above the ground. It suddenly explodes into two fragment of masses `m//4` and `3m//4`. An instant later, the smaller fragment is at `y=+15` cm. The larger fragment at this instant is atA. `-5 cm `B. `-20 cm `C. `+5cm `D. `(-45)/4cm`
Answer» Correct Answer - 1 The particle moving along x-axis, So, centre of mass will not move along y direction. `y_(cm)=0` `=(m_(1)y_(1)+m_(2)y_(2))/(m_(1)+m_(2)) =((m//4).15+(3m//4)y)/m` y=-5 cm

Discussion

23056.	The outer surface of the cardboard center of a paper towel roll: A. is a possible Gaussian surface B. cannot be a Gaussian surface because it encloses no charge C. cannot be a Gaussian surface since it is an insulator D. cannot be a Gaussian surface because it is not a closed surface E. none of the above
Answer» D. cannot be a Gaussian surface because it is not a closed surface

Discussion

23057.	An electron moves from point i to point f, in the direction of a uniform electric field. During this displacement:A. the work done by the field is positive and the potential energy of the electron-field system increases B. the work done by the field is negative and the potential energy of the electron-field system increases C. the work done by the field is positive and the potential energy of the electron-field system decreases D. the work done by the field is negative and the potential energy of the electron-field system decreases E. the work done by the field is positive and the potential energy of the electron-field system does not change
Answer» B. the work done by the field is negative and the potential energy of the electron-field system increases

Discussion

23058.	Correct graph of `y-1=x^(2)` is -A. B. C. D.
Answer» Correct Answer - 1 At y=1, x=0

Discussion

23059.	`int_(2)^(5)(1)/((2+3x))dx` is -A. `(15)/(2)`B. `(7)/(5)`C. `(1)/(3)l"n"(17)/(8)`D. `l"n"(17)/(8)`
Answer» Correct Answer - 3 `[(log(2+3x))/(3)]_(2)^(5)` `(1)/(3)(log17-log8)=(1)/(3)l n(17)/(8)`

Discussion

23060.	Give the characteristics of image formed by a plane mirror.
Answer» The image formed by a plane mirror is virtual, erect, and laterally inverted. The size of the image is equal to the size of the object. The image distance far behind the mirror is equal to the object distance in front of it. If an object is placed between two plane mirrors inclined at an angle 0, then the number of images n formed is as, \(n = (\frac{360}{θ}-1)\)

Discussion

23061.	If the collector resistor decreases to zero in a basebiased circuit, the load line will become a. Horizontal b. Vertical c. Useless d. Fla
Answer» The correct answer is: b. Vertical

Discussion

23062.	If the base supply voltage is disconnected, the collector-emitter voltage will equal a. 0 V b. 6 V c. 10.5 V d. Collector supply voltage
Answer» (d) Collector supply voltage

Discussion

23063.	If a transistor operates at the middle of the load line, an increase in the base resistance will move the Q point a. Down b. Up c. Nowhere d. Off the load line
Answer» The correct answer is: (a) Down

Discussion

23064.	Three different Q points are shown on a load line. The upper Q point represents the a. Minimum current gain b. Intermediate current gain c. Maximum current gain d. Cutoff point
Answer» (c) Maximum current gain

Discussion

23065.	If the collector resistor is open, the ac input voltage will a. Decrease b. Increase c. Remain the same d. Equal approximately zero
Answer» (a) Decrease

Discussion

23066.	If the emitter resistor is open, the ac input voltage will a. Decrease b. Increase c. Remain the same d. Equal zero
Answer» (b) Increase

Discussion

23067.	If any capacitor is open, the ac output voltage will a. Decrease b. Increase c. Remain the same d. Equal zero
Answer» (a) Decrease

Discussion

23068.	An open resistor has a. Infinite current through it b. Zero voltage across it c. Infinite voltage across it d. Zero current through it
Answer» (d) Zero current through it

Discussion

23069.	If the bypass capacitor is open, the ac input voltage will a. Decrease b. Increase c. Remain the same d. Equal zero
Answer» (b) Increase

Discussion

23070.	If the output coupling capacitor is open, the ac input voltage will a. Decrease b. Increase c. Remain the same d. Equal zero
Answer» (c) Remain the same

Discussion

23071.	If the load resistance is open, the ac output voltage will a. Decrease b. Increase c. Remain the same d. Equal zero
Answer» (b) Increase

Discussion

23072.	If the input coupling capacitor is open, the ac input voltage will a. Decrease b. Increase c. Remain the same d. Equal zero
Answer» (d) Equal zero

Discussion

23073.	A shorted resistor has a. Infinite current through it b. Zero voltage across it c. Infinite voltage across it d. Zero current through it
Answer» (b) Zero voltage across it

Discussion

23074.	A VCVS amplifier has no output voltage. A possible trouble is a. Shorted load resistor b. Open feedback resistor c. Excessive input voltage d. Open load resistor
Answer» (a) Shorted load resistor

Discussion

23075.	Negative feedback reduces the a. Feedback fraction b. Distortion c. Input offset voltage d. Loop gain
Answer» (b) Distortion

Discussion

23076.	The positive clamper adds a. A positive dc voltage to the input b. A negative dc voltage to the input c. An ac signal to the output d. A trip point to the input
Answer» (a) A positive dc voltage to the input

Discussion

23077.	A first-order stage cannot have a a. Butterworth response b. Chebyshev response c. Maximally-flat passband d. Rolloff rate of 20 dB per decade
Answer» (b) Chebyshev response

Discussion

23078.	If GBW is limited, the Q of the stage will a. Remain the same b. Double c. Decrease d. Increase
Answer» (d) Increase

Discussion

23079.	To correct for limited GBW, a designer may use a. A constant time delay b. Predistortion c. Linear phase shift d. A rippled passband
Answer» (b) Predistortion

Discussion

23080.	To detect when the input is greater than a particular value, use a a. Comparator b. Clamper c. Limiter d. Relaxation oscillator
Answer» (a) Comparator

Discussion

23081.	A window comparator a. Has only one usable threshold b. Uses hysteresis to speed up response c. Clamps the input positively d. Detects an input voltage between two limits
Answer» (d) Detects an input voltage between two limits

Discussion

23082.	VDB needs a. Only three resistors b. Only one supply c. Precision resistors d. More resistors to work better
Answer» (b) Only one supply

Discussion

23083.	The voltage that starts an oscillator is caused by a. Ripple from the power supply b. Noise voltage in resistors c. The input signal from a generator d. Positive feedback
Answer» (b) Noise voltage in resistors

Discussion

23084.	A lead circuit has a phase angle that is a. Between 0 and +90 degrees b. Greater than 90 degrees c. Between 0 and -90 degrees d. The same as the input voltage
Answer» (a) Between 0 and +90 degrees

Discussion

23085.	Initially, the loop gain of a Wien-bridge oscillator is a. 0 b. 1 c. Low d. High
Answer» The answer is: (d) High

Discussion

23086.	A Wien-bridge oscillator uses a. Positive feedback b. Negative feedback c. Both types of feedback d. An LC tank circuit
Answer» (c) Both types of feedback

Discussion

23087.	The Wien-bridge oscillator is useful a. At low frequencies b. At high frequencies c. With LC tank circuits d. At small input signals
Answer» (a) At low frequencies

Discussion

23088.	The common-mode rejection ratio is a. Very low b. Often expressed in decibels c. Equal to the voltage gain d. Equal to the common-mode voltage gain
Answer» (b) Often expressed in decibels

Discussion

23089.	The input offset current is usually a. Less than the input bias current b. Equal to zero c. Less than the input offset voltage d. Unimportant when a base resistor is used
Answer» (a) Less than the input bias current

Discussion

23090.	With Sallen-Key high-pass filters, the pole frequency must be a. Added to the K values b. Subtracted from the K values c. Multiplied by the K values d. Divided by the K values
Answer» (d) Divided by the K values

Discussion

23091.	When we trim a resistor, we are a. Making a fine adjustment b. Reducing its value c. Increasing its value d. Making a coarse adjustment
Answer» (a) Making a fine adjustment

Discussion

23092.	If an op amp has only a positive supply voltage, its output cannot a. Be negative b. Be zero c. Equal the supply voltage d. Be ac coupled
Answer» (a) Be negative

Discussion

23093.	A D/A converter with four inputs has a. Two outputs b. Four outputs c. Eight outputs d. Sixteen outputs
Answer» (d) Sixteen outputs

Discussion

23094.	When a JFET is used in an AGC circuit, it acts like a a. Switch b. Voltage-controlled current source c. Voltage-controlled resistance d. Capacitance
Answer» (c) Voltage-controlled resistance

Discussion

23095.	Link coupling refers to a. Capacitive coupling b. Transformer coupling c. Resistive coupling d. Power coupling
Answer» (b) Transformer coupling

Discussion

23096.	An op amp with a rail-to-rail output a. Has a current-boosted output b. Can swing all the way to either supply voltage c. Has a high output impedance d. Cannot be less than 0 V.
Answer» (b) Can swing all the way to either supply voltage

Discussion

23097.	The Q of a Sallen-Key second-order stage depends on the a. Voltage gain b. Center frequency c. Bandwidth d. GBW of the op amp
Answer» (a) Voltage gain

Discussion

23098.	The Hartley oscillator uses a. Negative feedback b. Two inductors c. A tungsten lamp d. A tickler coil
Answer» (b) Two inductors

Discussion

23099.	To vary the frequency of an LC oscillator, you can vary a. One resistor b. Two resistors c. Three resistors d. One capacitor
Answer» (d) One capacitor

Discussion

23100.	The material with the piezoelectric effect is a. Quartz b. Rochelle salts c. Tourmaline d. All the above
Answer» (d) All the above

Discussion

Explore topic-wise InterviewSolutions in .

What is the commercial unit of electric energy? Convert it into joules.

Out of 60 W and 40 W lamps which one has higher electrical resistance when in use?

Write two points of difference between electric energy and electric power.

What is meant by electric current? Name and define its SI unit. In a conductor electrons are flowing from B to A. What is the direction of conventional current? Give justification for your answer.

Correct graph of `y-1=x^(2)` is -A. B. C. D.

`int_(2)^(5)(1)/((2+3x))dx` is -A. `(15)/(2)`B. `(7)/(5)`C. `(1)/(3)l"n"(17)/(8)`D. `l"n"(17)/(8)`

Give the characteristics of image formed by a plane mirror.

If the collector resistor decreases to zero in a basebiased circuit, the load line will become a. Horizontal b. Vertical c. Useless d. Fla

If the base supply voltage is disconnected, the collector-emitter voltage will equal a. 0 V b. 6 V c. 10.5 V d. Collector supply voltage

If a transistor operates at the middle of the load line, an increase in the base resistance will move the Q point a. Down b. Up c. Nowhere d. Off the load line

Three different Q points are shown on a load line. The upper Q point represents the a. Minimum current gain b. Intermediate current gain c. Maximum current gain d. Cutoff point

If the collector resistor is open, the ac input voltage will a. Decrease b. Increase c. Remain the same d. Equal approximately zero

If the emitter resistor is open, the ac input voltage will a. Decrease b. Increase c. Remain the same d. Equal zero

If any capacitor is open, the ac output voltage will a. Decrease b. Increase c. Remain the same d. Equal zero

An open resistor has a. Infinite current through it b. Zero voltage across it c. Infinite voltage across it d. Zero current through it

If the bypass capacitor is open, the ac input voltage will a. Decrease b. Increase c. Remain the same d. Equal zero

If the output coupling capacitor is open, the ac input voltage will a. Decrease b. Increase c. Remain the same d. Equal zero

If the load resistance is open, the ac output voltage will a. Decrease b. Increase c. Remain the same d. Equal zero

If the input coupling capacitor is open, the ac input voltage will a. Decrease b. Increase c. Remain the same d. Equal zero

A shorted resistor has a. Infinite current through it b. Zero voltage across it c. Infinite voltage across it d. Zero current through it

A VCVS amplifier has no output voltage. A possible trouble is a. Shorted load resistor b. Open feedback resistor c. Excessive input voltage d. Open load resistor

Negative feedback reduces the a. Feedback fraction b. Distortion c. Input offset voltage d. Loop gain

The positive clamper adds a. A positive dc voltage to the input b. A negative dc voltage to the input c. An ac signal to the output d. A trip point to the input

A first-order stage cannot have a a. Butterworth response b. Chebyshev response c. Maximally-flat passband d. Rolloff rate of 20 dB per decade

If GBW is limited, the Q of the stage will a. Remain the same b. Double c. Decrease d. Increase

To correct for limited GBW, a designer may use a. A constant time delay b. Predistortion c. Linear phase shift d. A rippled passband

To detect when the input is greater than a particular value, use a a. Comparator b. Clamper c. Limiter d. Relaxation oscillator

A window comparator a. Has only one usable threshold b. Uses hysteresis to speed up response c. Clamps the input positively d. Detects an input voltage between two limits

VDB needs a. Only three resistors b. Only one supply c. Precision resistors d. More resistors to work better

The voltage that starts an oscillator is caused by a. Ripple from the power supply b. Noise voltage in resistors c. The input signal from a generator d. Positive feedback

A lead circuit has a phase angle that is a. Between 0 and +90 degrees b. Greater than 90 degrees c. Between 0 and -90 degrees d. The same as the input voltage

Initially, the loop gain of a Wien-bridge oscillator is a. 0 b. 1 c. Low d. High

A Wien-bridge oscillator uses a. Positive feedback b. Negative feedback c. Both types of feedback d. An LC tank circuit

The Wien-bridge oscillator is useful a. At low frequencies b. At high frequencies c. With LC tank circuits d. At small input signals

The common-mode rejection ratio is a. Very low b. Often expressed in decibels c. Equal to the voltage gain d. Equal to the common-mode voltage gain

The input offset current is usually a. Less than the input bias current b. Equal to zero c. Less than the input offset voltage d. Unimportant when a base resistor is used

With Sallen-Key high-pass filters, the pole frequency must be a. Added to the K values b. Subtracted from the K values c. Multiplied by the K values d. Divided by the K values

When we trim a resistor, we are a. Making a fine adjustment b. Reducing its value c. Increasing its value d. Making a coarse adjustment

If an op amp has only a positive supply voltage, its output cannot a. Be negative b. Be zero c. Equal the supply voltage d. Be ac coupled

A D/A converter with four inputs has a. Two outputs b. Four outputs c. Eight outputs d. Sixteen outputs

When a JFET is used in an AGC circuit, it acts like a a. Switch b. Voltage-controlled current source c. Voltage-controlled resistance d. Capacitance

Link coupling refers to a. Capacitive coupling b. Transformer coupling c. Resistive coupling d. Power coupling

An op amp with a rail-to-rail output a. Has a current-boosted output b. Can swing all the way to either supply voltage c. Has a high output impedance d. Cannot be less than 0 V.

The Q of a Sallen-Key second-order stage depends on the a. Voltage gain b. Center frequency c. Bandwidth d. GBW of the op amp

The Hartley oscillator uses a. Negative feedback b. Two inductors c. A tungsten lamp d. A tickler coil

To vary the frequency of an LC oscillator, you can vary a. One resistor b. Two resistors c. Three resistors d. One capacitor

The material with the piezoelectric effect is a. Quartz b. Rochelle salts c. Tourmaline d. All the above