EC
Engineering Classroom
by Himalay Sen

Exams

Prepare for your next test with our collection of exam-based practice sets and question banks designed for effective assessment and revision.

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
2041. ডি-হিউমিডিফায়ারের কাজ কী?
বাতাসের আর্দ্রতা কমায়
তাপমাত্রা নিয়ন্ত্রণ করে
উভয় কাজ করে
কোনোটিই না
ব্যাখ্যা: ইলেকট্রিক ডিহিউমিডিফায়ারের কাজ হলো বাতাসের জলীয়কণা শোষণ করে এবং আর্দ্রতাকে কমিয়ে ঘর, আসবাবপত্র ও যন্ত্রপাতিকে রক্ষা করা।
2042. The true statement for a series and a parallel de circuit is--
powers are additive
current are additive
element have individual current
voltage are additive
ব্যাখ্যা: ব্যাখ্যা: Powers are additive in both series and Parrallel. Currents are additive in parallel circuits whereas voltages are additive in series circuit.
2043. । মাইক্রোওয়েভ ওভেনে কোন ধরনের মোটর ব্যবহার করা হয়?
ইন্ডাকশন মোটর
সিনক্রোনাস মোটর
ব্লোয়ার মোটর
সিরিজ মোটর
2044. Electrical appliances are connected in parallel because it-
Is a simple circuit
Draws less current
Results in reduced power loss
Makes the operation of appliances independent of each other
2047. Three resistance 14.5Ω, 25.5Ω and 60Ω are connected in series across 200V. What will be the voltage drop across 14.5Ω?
29V
14V
13.5V
18V
2049. Kirchhoff's current law at a junction deals with-
Conversation of energy
Conversation of momentum
Conversation of charge
Conversation of angular momentum
ব্যাখ্যা: ব্যাখ্যা: Kirchhoff's Current Law (KCL) is Kirchhoff's first law deals with the conservation of charge entering and leaving a junciton
2051. What happens if an electric bulb rated at 220V is connected to 220V, 5 Hz ac source? The bulb-
does not glow
fuses
glows continuously
glows intermittently
ব্যাখ্যা: ব্যাখ্যাঃ When you give 5Hz supply, frequency is too low. Normally when 50 Hz (50 times a second AC is given, it will get max volts twice in each cycle, that is it gets varing voltage from 0 to 220'a hundred times a second, in negative and positive cycles), the white hot blulb filament has no time to cool. Hence it appears to us as glowing continuously. But when you drastically reduce to 5 Hz it has times to cool off and again get white when hot. You will observe the blub will flash at rate of 10 times per seconde
2052. A wire has a resistance of 122. It is bent in the form of a circle. The effective resistance between the two points on any diameter of the circle is--
12Ω
24Ω
2053. An external resistance R is connected to a cell of internal resistance r. The maximum current flows in the external resistance when-
R<r
R=r
R>r
None of the above
2054. মাইক্রোওয়েভ ওভেনের কুকিং সুইচ অন করলে কী কী সক্রিয় হয়?
ব্লোয়ার মোটর
কুকিং রিলে
ম্যাগনেট্রন টিউব
সবগুলো
2056. If the length and cross section of a piece of conductor are both doubled what will be its resistance (initial resistance R)?
4R
2R
R
1 /4 R
2057. Two equal resistances are connected in series across a certain supply. If the resistances are now connected in parallel, the power produced will become-
two-times
four times
one-half
one-fourth
ব্যাখ্যা: ব্যাখ্যাঃ if two equal resistance connected in series across a certain supply are now connected in parallel across the same supply, the power produced will be four times that of series connection.
2058. মাইক্রোওয়েভ ওভেন কোন নীতিতে কাজ করে?
কেমিক্যাল নীতিতে
মেকানিক্যাল নীতিতে
তাপনীতিতে
ক ও খ
2059. The internal resistance of a cell of e.m.f 2V is 0.1Ω It is connected to a resistance of 3.9Ω. The voltage across the cell is-
0.5V
1.9V
1.95V
2V