টার্গেট - BPSC নন ডিপার্টমেন্ট রিটেন বইটি বর্তমানে BPSC রিটেন পরীক্ষার জন্য সেরা। BPSC এর বিগত সালের সকল লিখিত পরীক্ষার প্রশ্নের উত্তর এই বইয়ে দেওয়া হয়েছে।
ব্যাখ্যা: ব্যাখ্যা: Induction type instruments are commonly used in power system measurement. These types of instruments are used only for AC measurements.
ব্যাখ্যা: ব্যাখ্যা : Permanent magnets are made from hard ferromagnetic materials such as alnilco and ferrite alloy that are subjected to special processing in a strong magnetic field during manufacture to align their internal microcrystalline structure, making them very hard to demagnetize.
ব্যাখ্যা: ব্যাখ্যা: To avoid the effect of stray magnetic field in A.C bridges we can use magnetic screening or magnetic shielding. Magnetic screening is a technique used to prevent magnetization of metals nearby a magnet or current carrying conductor which is a source of magnetic field.
ব্যাখ্যা: ব্যাখ্যা: Alternating current is measured by induction ammeter because the operation of induction type instruments depends on the production of torque due to the reaction between two magnetic fluses having some phase difference between the flux of an AC magnet and the eddy current induced by this flux.
ব্যাখ্যা: ব্যাখ্যা: The instrument which represents the measured value in the form of the digital number (numaric number) is known is digital instruments.
4389.
A current transformer has a single-turn primary and a 200-turn secondary and is used to measure a.c. current with the help of a standard 5A a.c. ammeter. This arrangement can measure a line current of up to amperes.
ব্যাখ্যা: ব্যাখ্যা : The quality factor or the Q factor of an inductor at the operating frequency w is defined as the ratio of reactance of the coil to its resistance.none of the above ব্যাখ্যা : The quality factor or the Q factor of an inductor at the operating frequency w is defined as the ratio of reactance of the coil to its resistance.
4392.
The megger (Megaohmmeter) is exclusively designed for measuring-
ব্যাখ্যা: ব্যাখ্যা: The megger instrument for measuring the insulation resistance of electrical device was introduced by the British firm of Evershed and Vignoles in 1905. It can measure very high resistance like hundreds of megaohoms range
4393.
The pointer of an indicating instrument is generally made of-
ব্যাখ্যা: ব্যাখ্যা: পয়েন্টারের আকার-আকৃতি করে। সকল ক্ষেত্রে পয়েন্টারের ওজন ও জড়তা যতদূর সম্ভব কম রাখা হয়, যাতে মুভিং সিস্টেমের বিয়ারিং-এর উপর বুঝা কম হয়। হালকা করার জন্যে অ্যালুমিনিয়ামের পাত অথবা ইনস্ট্রমেন্টের ধরনের উপর নির্ভর টিউব, পয়েন্টার হিসেবে ব্যবহৃত হয়।
4394.
The pointer of an indicating instrument should be--
ব্যাখ্যা: ব্যাখ্যা: In an energy meter, a barking torque is produced to maintain a steady speed and equal to driving torque. A permanent magnet positioned near the edge of the aluminum disc from the braking system.
4396.
The disc of an instrument using eddy current damping should be of-
ব্যাখ্যা: ব্যাখ্যা: Megger is a Portable instrument to measure high insulation resistances. Ii basically works on the principle of electromagnetic induction. The electrical power to a meggar is provided by permanent magnet D.C generator.
4399.
To measure high frequency currents, we mostly use---ammeter.
ব্যাখ্যা: ব্যাখ্যা: Creeping in energy meter or watt-hour meters is the phenomenon in which the aluminium dise rotates continuously when only the voltage is supplied to the pressure coil and no current flows through the current coil.