EC
Engineering Classroom
by Himalay Sen

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সালের প্রশ্ন

Access past board exam questions organized by year and subject to help you understand patterns, improve preparation, and boost your exam performance.

MCQ
4682. 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
4684. 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
4686. Z=50/30 হলে এর পাওয়ার ফ্যাক্টর কত হবে?
ইউনিটি
শূন্য
0.866 (লিডিং)
0.866 (ল্যাগিং)
4689. The capacitive reactance of a circuit is-frequency.
independent of
inversely proportional to
directly proportional to
none of the above
4690. Inductance opposes --in current in a circuit.
only increase
change
only decrease
none of the above
ব্যাখ্যা: 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. If a phase is multiplied by j, then –
only its magnitude changes
only its direction changes
both magnitude & direction changes.
none of above
ব্যাখ্যা: 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.
4692. Inductance opposes --in current in a circuit
only increase
change
only decrease
none of the above
ব্যাখ্যা: 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.
4696. 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
4697. 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