#### Before checking all questions and answer try below free mock test which. All questions are asked in 21-feb-2021 paper.

[ays_quiz id=”12″]

For subject wise if you want to give paper then click here

## All Questions and Answer of MRPL 21-feb-2021

#### A cell of emf x and internal resistance y is connected to a resistance y. The potential difference between the terminals of the cell is

• x/2
• x/2y
• 2x/y
• x/(x+y)

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x/2

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#### The ohm’s law deals with the relation between

• charge and resistance
• charge and capacity
• current and potential difference.
• capacity and potential difference.

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current and potential difference.

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#### Potential inside a hollow charged sphere is

• same as on its sphere
• greater than on its surface
• less than on its surface
• zero

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same as on its sphere

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#### Capacitance of a parallel plate capacitor decreases by

• increasing the area of plates
• increasing the distance between the plates
• putting a dielectric between the plates
• decreasing the distance between the plates

[bg_collapse view=”button-orange” color=”#4a4949″ expand_text=”Show Answer” collapse_text=”Show Less” ]increasing the distance between the plates [/bg_collapse]

#### The capacitance of the two capacitors are in the ratio 1:2. When they are connected in parallel across supply voltage v, their charges will be in the ratio of

• 1:2
• 2:1
• 3:2
• 2:3

[bg_collapse view=”button-orange” color=”#4a4949″ expand_text=”Show Answer” collapse_text=”Show Less” ]1:2[/bg_collapse]

#### The capacity of a cell depends upon

• Nature of plates material and electrolyte
• Sizes of the plates and the quality of electrolyte
• Both (A) and (B)
• None of the above

[bg_collapse view=”button-orange” color=”#4a4949″ expand_text=”Show Answer” collapse_text=”Show Less” ]Sizes of the plates and the quality of electrolyte[/bg_collapse]

#### When an organic compound is dissolved in water, the attractive forces between the charged atom reduce tremendously and they are separated this is called.

• Decomposition
• Deionisation
• Ionisation
• None of the above

[bg_collapse view=”button-orange” color=”#4a4949″ expand_text=”Show Answer” collapse_text=”Show Less” ]Ionisation [/bg_collapse]

#### Hysteresis loss in a magnetic material depends upon

• Area of hysteresis loop
• Frequency of reversed of field
• Volume of magnetic material
• All (A), (B) and (C)

[bg_collapse view=”button-orange” color=”#4a4949″ expand_text=”Show Answer” collapse_text=”Show Less” ]All (A), (B) and (C)

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#### Wheatstone bridge is used to measure

• Voltage
• Resistance
• Current
• Power

[bg_collapse view=”button-orange” color=”#4a4949″ expand_text=”Show Answer” collapse_text=”Show Less” ]Resistance [/bg_collapse]

#### The three resistors each of r ohm are connected in star. When they are transformed into delta connections, the resistance of each arm will be

• 2R ohm
• 3R ohm
• 4R ohm
• R/2 ohm

[bg_collapse view=”button-orange” color=”#4a4949″ expand_text=”Show Answer” collapse_text=”Show Less” ]3R ohm

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#### When a source is delivering maximum power to the load, the efficiency will be

• Maximum
• Before 50%
• Above 50%
• 50%

[bg_collapse view=”button-orange” color=”#4a4949″ expand_text=”Show Answer” collapse_text=”Show Less” ]50%[/bg_collapse]

#### An alternating quantity which attains its positive maximum value prior to the other is called the

• In phase quantity
• Lagging quantity
• None of the above

#### If a sinusoidal wave has frequency of 50 Hz with 15 ampere rms value. Which of the following equation represents?

• 15sin5Ot
• 30sin25t
• 42.42sin 100t
• 21.21sin314t

[bg_collapse view=”button-orange” color=”#4a4949″ expand_text=”Show Answer” collapse_text=”Show Less” ]21.21sin314t [/bg_collapse]

#### When a sinusoidal voltage is applied across a R-L series circuit having R XL, the phase angle will be

• 90°
• 30°
• 45°

[bg_collapse view=”button-orange” color=”#4a4949″ expand_text=”Show Answer” collapse_text=”Show Less” ]45°

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#### The shunt used in the millimetre

• Will extend the range and increases the resistance
• Will extend the range and decreases the meter resistance
• Will decrease the range and meter resistance
• Will decrease the range and increases the meter resistance

[bg_collapse view=”button-orange” color=”#4a4949″ expand_text=”Show Answer” collapse_text=”Show Less” ]Will extend the range and decreases the meter resistance [/bg_collapse]

#### A signal of 10mV at 75MHz is to be measured. Which of the following instruments can be used

• VTVM
• Cathode rayoscilloscope
• Moving iron voltmeter
• Digital multimeter

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Cathode rayoscilloscope

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#### The pressure coil of a dynamometer type wattmeter is

• Highly inductive
• Highly resistive
• Purely resistive
• Purely inductive

[bg_collapse view=”button-orange” color=”#4a4949″ expand_text=”Show Answer” collapse_text=”Show Less” ]Highly resistive [/bg_collapse]

#### The dc series motors are preferred for traction applications because

• The torque is proportional armature current
• The torque is proportional to the square root of armature current
• The torque is proportional to square of armature Current and the speed is inversely proportional to the torque.
• Torque and speed are inversely proportional to armature current

[bg_collapse view=”button-orange” color=”#4a4949″ expand_text=”Show Answer” collapse_text=”Show Less” ]The torque is proportional to square of armature Current and the speed is inversely proportional to the torque. [/bg_collapse]

#### What would happen if the field of d.c shunt motor is opened

• The speed of the motor will be reduced
• It will continue to run at its normal speed
• The speed of the motor becomes very high and may damage it.
• The current in the armature will decreases

[bg_collapse view=”button-orange” color=”#4a4949″ expand_text=”Show Answer” collapse_text=”Show Less” ]The speed of the motor becomes very high and may damage it. [/bg_collapse]

#### The eddy current loss in the transformers occurs in the

• Primary winding
• Core
• Secondary winding
• None of the above

[bg_collapse view=”button-orange” color=”#4a4949″ expand_text=”Show Answer” collapse_text=”Show Less” ]Core[/bg_collapse]

#### 1:5 step-up transformer has 120V across the primary and 600 ohms resistance across the secondary. Assuming 100% efficiency, the primary current will be:

• 0.2 Amp
• 5 Amp
• 10 Amp
• 20 Amp

[bg_collapse view=”button-orange” color=”#4a4949″ expand_text=”Show Answer” collapse_text=”Show Less” ]10Amp[/bg_collapse]

#### The short circuit test in the transformers is performed to determine

• The iron loss at any load
• The hysteresis loss
• The eddy current loss

[bg_collapse view=”button-orange” color=”#4a4949″ expand_text=”Show Answer” collapse_text=”Show Less” ]The copper loss at any load or any full load [/bg_collapse]

#### Regenerative method of braking is based on that

• Back emf is less than the applied voltage
• Back emf is equal to the applied voltage
• Back emf is more than the applied voltage
• None of the above

[bg_collapse view=”button-orange” color=”#4a4949″ expand_text=”Show Answer” collapse_text=”Show Less” ]Back emf is more than the applied voltage [/bg_collapse]

#### Which of the following can be used to control the speed of a d.c motor?

• Thermistor
• Thyristor
• Thyratron
• Transistor

[bg_collapse view=”button-orange” color=”#4a4949″ expand_text=”Show Answer” collapse_text=”Show Less” ]Thyristor

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#### Which of the following motors is most suitable for signaling devices and many kinds of timers

• d.c shunt motor
• d.c series motor
• Inductance motor
• Reluctance motor

[bg_collapse view=”button-orange” color=”#4a4949″ expand_text=”Show Answer” collapse_text=”Show Less” ]Reluctance motor

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#### Sparking at the commutators of a dc motor may result in

• Damage to the commutator’s segments
• Damage to the commutator’s insulation
• Increased power consumption
• All of the above

[bg_collapse view=”button-orange” color=”#4a4949″ expand_text=”Show Answer” collapse_text=”Show Less” ]All of the above

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According to Fleming’s right hand rule for finding the direction induced emf, when induced finger points in the direction of induced emf, forefinger will point the direction of

• Motion of conductor
• Lines offorce
• Either of the above
• None of the above

[bg_collapse view=”button-orange” color=”#4a4949″ expand_text=”Show Answer” collapse_text=”Show Less” ]Lines offorce [/bg_collapse]

#### The full load copper loss and iron loss of a transformer are 6400W and 5000W respectively the copper loss and iron loss at half load will be respectively.

• 3200W and 2500W
• 3200W and 5200W
• 1600W and 1250W
• 1600W and 5000W

[bg_collapse view=”button-orange” color=”#4a4949″ expand_text=”Show Answer” collapse_text=”Show Less” ]1600W and 5000W
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#### A 6 pole, 3 phase alternator running at 1000rpm supplies to an 8 pole, 3 phase induction motor which has a rotor current of frequency 2Hz. The speed at which the motor operates is.

• 1000 rpm
• 960 rpm
• 750 rpm
• 720 rpm

[bg_collapse view=”button-orange” color=”#4a4949″ expand_text=”Show Answer” collapse_text=”Show Less” ]720 rpm[/bg_collapse]

#### The crawling in the induction motor Is caused by

• Improper design of stator lamination
• Low voltage supply
• Harmonics developed in motor

[bg_collapse view=”button-orange” color=”#4a4949″ expand_text=”Show Answer” collapse_text=”Show Less” ]Harmonics developed in motor [/bg_collapse]

#### The use of higher flux density in the transformer design

• Reduces the weight per kva
• Increases the weight per kva
• Has no relation with the weight of transformers
• Increases the weight per kw

[bg_collapse view=”button-orange” color=”#4a4949″ expand_text=”Show Answer” collapse_text=”Show Less” ]Reduces the weight per kva [/bg_collapse]

#### In hard-tool applications which one of the following single-phase motors is used

• Capacitor start motor
• Capacitor run motor
• AC series motor

[bg_collapse view=”button-orange” color=”#4a4949″ expand_text=”Show Answer” collapse_text=”Show Less” ]AC series motor [/bg_collapse]

#### What is the angle between the induced voltage and supply voltage of a synchronous motor under running generation?

• Zero
• Greater than zero but =< 90°
• Between 90° and 180°
• 180°

[bg_collapse view=”button-orange” color=”#4a4949″ expand_text=”Show Answer” collapse_text=”Show Less” ]Greater than zero but =< 90° [/bg_collapse]

#### How can reactive power delivered by a synchronous generator be controlled?

• By changing the prime moves input
• By changing the excitation
• By changing the direction of rotation
• By hanging the prime moves speed

[bg_collapse view=”button-orange” color=”#4a4949″ expand_text=”Show Answer” collapse_text=”Show Less” ]By changing the excitation[/bg_collapse]

#### When does a synchronous motor operate with leading power factor current?

• While it is under excited
• While it is critically excited
• While it is over excited
• While it is heavily loaded

[bg_collapse view=”button-orange” color=”#4a4949″ expand_text=”Show Answer” collapse_text=”Show Less” ]While it is over excited

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#### In an induction motor what is the ratio of rotor copper-loss and rotor input

• 1/s
• s
• (1-s)
• s/(1-s)

[bg_collapse view=”button-orange” color=”#4a4949″ expand_text=”Show Answer” collapse_text=”Show Less” ]s[/bg_collapse]

#### Select the correct answers using the code given below

• 2, 3 and 4
• 3 and 4
• 1, 2 and 3
• 1, 2 and 4

[bg_collapse view=”button-orange” color=”#4a4949″ expand_text=”Show Answer” collapse_text=”Show Less” ]1, 2 and 4[/bg_collapse]

#### The pressure at the furnace is minimum in case of

• Force draught system
• Induced draught system
• Balanced draught system
• Natural draught System

[bg_collapse view=”button-orange” color=”#4a4949″ expand_text=”Show Answer” collapse_text=”Show Less” ]Balanced draught system

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• Aluminium
• Cast iron