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1.0.0
MCQ
4681. The average value of a sinusoidal current is 100A. Its rms value is-
70.7A
63.7A
141.4A
111A
4682. Two identical capacitors are connected in parallel and charged to a potential of V. They are separated and then connected in series. The potential across the series combination is-
V
3V
4V
2V
4683. If a phase is multiplied by j, then –
only its magnitude changes
only its direction changes
both magnitude & direction changes.
none of above
ব্যাখ্যা: It we multiplied by then the phase direction will rotate through a fixed angle of 90° in an anticlockwise direction. In each successive rotation, the magnitude of the vector always remains the same.
4684. Four capacitors each of 40µF are connected in parallel, the equivalent capacitance will be-
160µF
40µF
10µF
5µF
4685. Admittance এর একক কী?
Mho
Simens
Ohm
কওখ
4686. The phase sequence of a three-phase system is RYB. The other possible phase sequence can be-
BRY
YRB
RBY
none of the above
4687. The capacitive reactance of a circuit is-frequency.
independent of
inversely proportional to
directly proportional to
none of the above
4688. What is the peak-to-peak value for 120V ac?
240V
339V
480V
391V
4689. In a series R.L circuit, voltage across resistor inductor are 3V and 4V respectively, then what is the applied voltage?
7V
4V
5V
3V
4690. At parallel resonance-
circuit impedance is minimum
power factor is zero
line current is maximum
power factor is unity
4691. What is the power frequency (Hz) of Bangladesh?
30
60
50
None
4692. যদি Delta সার্কিটে একটি phase open করা হয় তাহলে Total power এর কত অংশ কমবে?
1/3 অংশ
1/2 অংশ
2 অংশ
কোনোটিই নয়
4693. Capacitive susceptance এর একক কী?
Mho
Simens
Ohm
কওখ
4694. The unit of inductance—
Inducta
henry
inductive reactance
ohm
4695. যদি Star সার্কিটে একটি Phase open করা হয় তাহলে total power এর কত অংশ কমবে?
1/3 অংশ
1/2 অংশ
2 অংশ
কোনোটিই নয়
4696. At parallel resonance the circuit impedance equals to-
L/CR
LC/R
RL/C
CR/L
4697. Inductance opposes --in current in a circuit
only increase
change
only decrease
none of the above
ব্যাখ্যা : According to Lenz's law, the induced voltage has a polarity (direction) which opposes the change in current that created it. As a result, inductors oppose any changes in current.
4698. একটি Heater 230/250 voltage-এ উত্তপ্ত হয়। যখন 250 volt সরবরাহ পায় তখন 5 Amp বিদ্যুৎ প্রবাহিত হয়, তবে যখন 230 volt সরবরাহ পায় তখন কত বিদ্যুৎ প্রবাহিত হবে?
3.6
5.6
4.6
কোনোটিই নয়
4699. RMS value of the instantaneous ac voltage V = 300 is-
300x√2
300/√2
300x√3
300/√3
4700. Inductance opposes --in current in a circuit.
only increase
change
only decrease
none of the above
ব্যাখ্যা : According to Lenz's law, the induced voltage has a polarity (direction) which opposes the change in current that created it. As a result, inductors oppose any changes in current.