EC
Engineering Classroom
by Himalay Sen

Exams

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Board Questions

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

MCQ
4684. 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.
4686. 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
4687. 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.
4688. 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.
4689. 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
4693. The capacitive reactance of a circuit is-frequency.
independent of
inversely proportional to
directly proportional to
none of the above
4696. 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
4699. 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