Image
1.0.0
MCQ
4681. 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.
4682. 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
4683. 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
4684. The unit of inductance—
Inducta
henry
inductive reactance
ohm
4685. The capacitive reactance of a circuit is-frequency.
independent of
inversely proportional to
directly proportional to
none of the above
4686. 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
4687. RMS value of the instantaneous ac voltage V = 300 is-
300x√2
300/√2
300x√3
300/√3
4688. What is the peak-to-peak value for 120V ac?
240V
339V
480V
391V
4689. At parallel resonance-
circuit impedance is minimum
power factor is zero
line current is maximum
power factor is unity
4690. 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.
4691. The phase sequence of a three-phase system is RYB. The other possible phase sequence can be-
BRY
YRB
RBY
none of the above
4692. Admittance এর একক কী?
Mho
Simens
Ohm
কওখ
4693. At parallel resonance the circuit impedance equals to-
L/CR
LC/R
RL/C
CR/L
4694. Four capacitors each of 40µF are connected in parallel, the equivalent capacitance will be-
160µF
40µF
10µF
5µF
4695. 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.
4696. The average value of a sinusoidal current is 100A. Its rms value is-
70.7A
63.7A
141.4A
111A
4697. Capacitive susceptance এর একক কী?
Mho
Simens
Ohm
কওখ
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. 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
4700. What is the power frequency (Hz) of Bangladesh?
30
60
50
None