Network theory objective questions with explanation 01 to 20

Network theory objective questions with explanation 01 to 20

Q no 1. Thevenin resistance Rth is found

A ) by removing voltage sources along with their internal resistance

B ) by short - circuiting the given two terminal

C ) between any two open terminals

D ) between same open terminals as for Eth

explanation

               answer : D ) between same open terminals as for Eth 

Q no 2. " In any linear bilateral network , if a source of emf E in any branch produces a current I in any other branch , then same emf acting in the second branch would produce the same current I in the first branch. "

The above statement is associated with
A ) Compensation theorem
B ) superposition theorem
C ) reciprocity theorem
D ) none of the above

explanation

               answer : C ) reciprocity theorem

Q no 3. " In any network containing more than one source of the end the current in any branch is the algebraic sum of a number of individuals fictitious current ( the number being equal to the number of sources of emf ) each of which is due to separate action of each source of emf , taken in order , when the remaining sources of emf are replaced by conductor  , the resistance of which are equal to the internal resistance of the respective sources . "
The above statement associated with
A ) thevenin theorem
B ) Norton theorem
C ) superposition theorem
D ) none of the above

explanation

               answer : C ) superposition theorem

Q no 4. Efficiency of power transfer when maximum transfer of power occurs is
A ) 100 %
B ) 80 %
C ) 75 %
D ) 50 %

explanation

               answer : D ) 50 %

Q no 5. For high efficiency of transfer of power , internal resistance of the source should be
A ) equal to the load resistance
B ) less than the load resistance
C ) more than the load resistance
D ) none of the above

explanation

               answer : B ) less than the load resistance

Q no 6. For maximum transfer of power , internal resistance of the source should be
A ) equal to the load resistance
B ) less than the load resistance
C ) more than the load resistance
D ) none of the above

explanation

               answer : A ) equal to the load resistance

Q no 7. If the energy is supplied from a source , whose resistance is 1 ohm , to a load of 100 ohms the source will be
A ) a voltage source
B ) a current source
C ) both of above
D ) none of the above

explanation

               answer : C ) both of above

Q no 8. Application of norton's theorem to a circuit yields
A ) equivalent current source and impedance in series
B ) equivalent current source and impedance in parallel
C ) equivalent impedance
D ) equivalent current source

explanation

               answer : A ) equivalent current source and impedance in series

Q no 9. In series resonant circuit , increasing inductance  to its twice value and reducing capacitance to its half value
A ) will change the maximum value of current at resonance
B ) will change the resonance frequency
C ) will change the impedance at resonance frequency
D ) will increase the selectivity of the circuit

explanation

               answer : D ) will increase the selectivity of the circuit

Q no 10. Inductance affects the direct current
A ) only at the time of turning off
B ) only at the time of turning on
C ) at the time of turning on and off
D ) at all times of operations

explanation

               answer : C ) at the time of turning on and off

Q no 11. In any ac circuit always
A ) apparent power is more than actual power
B ) reactive power is more than apparent power
C ) actual power is more than the reactive power
D ) reaction power is more than actual power

explanation

               answer : A ) apparent power is more than actual power

Q no 12. Which of the following circuit components opposes the change in the circuit voltage ?
A) inductance
B ) capacitance
C ) conductance
D ) resistance

explanation

               answer : B ) capacitance

Q no 13. Pure inductive circuit takes power from the AC line when
A ) applied voltage decreases but current  increases
B ) applied voltage increases but current decreases
C ) both applied voltage and current increases
D ) both applied voltage and current decreases

explanation

               answer : A ) applied voltage decreases but current  increases

Q no 14. Power factor of magnetising components  of current of a transformer is
A ) 0.8 lag
B ) 0.8 lead
C ) zero
D ) unity

explanation

               answer : C ) zero

Q no 15. The physical quantities of resistance , inductance and capacitance are respectively R , L and C . The combination which have dimensions of frequency
A ) C / L
B ) R / L
C ) 1/ RC
D )  1  / √ LC

explanation

               answer : D )  1  / √ LC

Q no 16. The safest value of current the Human body can carry for than more than 3 second is :
A ) 4 mA
B ) 9 mA
C ) 15 mA
D ) 25 mA

explanation

               answer : B ) 9 mA

Q no 17.The effective resistance of an iron cored choke working on ordinary supply frequency is more than its true resistance because of
A ) iron loss in core
B ) skin effect
C ) increase in temperature
D ) capacitance effect between adjacent coil turns

explanation

               answer : A ) iron loss in core

Q no 18. All definition of power factor of a series RLC circuit are correct except
A ) ratio of net reactance and impedance
B ) ratio of KW and KVA
C ) ratio of R and Z
D ) ratio of W and VA

explanation

               answer : A ) ratio of net reactance and impedance

Q no 19. What will be the phase angle between two alternating wave of equal frequency , when one wave attain maximum value the other is at zero value ?
A ) 0°
B ) 45°
C ) 90 °
D ) 180 °

explanation

               answer : C ) 90 °

Q no 20. The power is measured in terms of decibels in case of
A ) electronic equipment
B ) transformer
C ) current transformer
D ) auto transformer

explanation

               answer : A ) electronic equipment

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