Phase advancers are used for which among the following machines? A) Transformers B) Synchronous machines. C) Induction motors. D) None o...

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## Wednesday, May 29, 2019

## What is the advantage of the static capacitors?

What is the advantage of the static capacitors? A) Low losses. B) Easy installation. C) Lower maintenance. D) All of the above. Show A...

## When the power factor in the transmission line is leading, which device is employed at substation to reduce the power factor

When the power factor in the transmission line is leading, which device is employed at substation to reduce the power factor A) CVT B) Rea...

## Power factor can be improved by connecting which among these?

Power factor can be improved by connecting which among these? A) Static capacitors B) Phase Advancer. C) Synchronous condensers. D) All ...

## In resonance condition (XL = XC) power factor

In resonance condition (XL = XC) power factor– A) lagging B) leading C) unity D) zero Show Answer Ans: C) unity "Show Answ...

## A transformer has negative voltage regulation when its load power factor is

A transformer has negative voltage regulation when its load power factor is– A) lagging B) leading C) unity D) zero Show Answer Ans:...

## For which among the following consumers is penalty imposed for low power factor in Bangladesh?

For which among the following consumers is penalty imposed for low power factor in Bangladesh? A) Residential and commercial consumers. B)...

## The primary reason for the low power factor is due to the installation of

The primary reason for the low power factor is due to the installation of A) Commutator motors B) DC motors C) Synchronous motors D) Ind...

## Commonly Power factor improve by

Commonly Power factor improve by— A) Resistor bank. B) Transformer Bank C) Capacitor Bank D) Inductor bank Show Answer Ans: C) Capac...

## In a circuit low reactive power compared to true power indicates

In a circuit low reactive power compared to true power indicates A) Low power factor B) High power factor. C) Low efficiency D) High eff...

## For a consumer what is the most economical power factor?

For a consumer what is the most economical power factor? A) 0.25 – 0.5 lagging. B) 0.25 – 0.5 leading. C) 0.85 – 0.95 lagging. D) 0.85 –...

## Lower power factor is usually not due to

Lower power factor is usually not due to A) Discharge lamp. B) Arc lamps. C) Incandescent lamps. D) Induction furnace Show Answer An...

## Tuesday, May 28, 2019

## Which among the following happens in a low power factor?

Which among the following happens in a low power factor? A) Large kVA rating of the equipment. B) Greater conductor size. C) Reduced hand...

## If the power factor is unity, its reactive power is

If the power factor is unity, its reactive power is A) zero B) equal to apparant power C) equal to real power D) one Show Answer Ans...

## In an ac circuit i sin φ is called the _ component of the current

In an ac circuit i sin φ is called the _ component of the current A) Wattless B) Reactive C) Quadrature D) All the above Show Answer ...

## What is maximum value of power factor?

What is maximum value of power factor? A) 0.5 B) 0.95 C) 1 D) 1.5 Show Answer Ans: C) 1 "Show Answer" লেখায় ক্লিক ...

## The power factor of ordinary bulb is—

The power factor of ordinary bulb is— A) lag B) lead C) unity D) None of above Show Answer Ans: C) unity "Show Answer"...

## The power factor of ac circuit lies between

The power factor of ac circuit lies between A) 0 and 1 B) -1 and 1 C) 0 and -1 D) None of above Show Answer Ans: A) 0 and 1 &quo...

## In a R-C series circuit, power factor—

In a R-C series circuit, power factor— A) lag B) lead C) unity D) None of above Show Answer Ans: B) lead "Show Answer"...

## In a R-L series circuit, power factor—

In a R-L series circuit, power factor— A) lag B) lead C) unity D) None of above Show Answer Ans: A) lag "Show Answer" ...

## The power factor of an AC circuit is given by—

The power factor of an AC circuit is given by— A) cos φ B) sin φ C) tan φ D) None of above Show Answer Ans: A) cos φ "Show ...

## Power factor is the ratio of _ and apparent power.

Power factor is the ratio of _ and apparent power. A) Reactive power B) Active power C) Load factor D) Maximum demand Show Answer An...

## Disadvantages of Low Power Factor

Lower power factor on a line means that higher current is flowing through it, so for low/poor power factor: 1) Large line losses (Copper L...

## Causes of low Power Factor

Causes of low Power Factor: 1. Single phase and three phase induction Motors. 2. Varying Load in Power System. 3. Transformers. 4. Electric...

## Keeping power factor in leading shows more KW & less KVA? Is it correct or not.?

This statement is incorrect. If the apparent power is 100KVA, at unity power factor the real power is 100kW. If PF = +/-0.95 (lead or lag),...

## How power factor is improved by synchronous Condenser?

When a Synchronous motor operates at No-Load condition and over exited condition then it’s called a synchronous Condenser. Whenever a Synch...

## What are the methods for power factor improvement?

Improving power factor means reducing the phase difference between voltage and current. There are various methods for increasing power fact...

## Why need power factor correction?

Power factor correction will improve voltage levels in the power system, reduces losses which will increase system capacity, eliminates pow...

## Unity, Lagging, Leading power factor

In AC circuits, the power factor can be anywhere between 0 and 1.0 depending on the passive components within the connected load. For a r...

## When the power factor will be leading?

The capacitor in the ac circuit is offering a reactance (X) to the flow of current. Inductive reactance, X=1/2πfC, where f is the supply fr...

## When power factor will be lagging?

The inductor in the ac circuit is offering a reactance (X) to the flow of current. Inductive reactance, X=2πfL, where f is the supply frequ...

## What is the Practical values of power factor?

The power factor can get values in the range from 0 to 1 When all the power is reactive power with no real power (usually inductive or ...

## What is Power Factor?

Power Factor may be defined as: The power factor is equal to the real or true power (P) in watts (W) divided by the apparent power (S) in ...

## If a wire conductor of 0.2 ohm resistance is doubled in length, its resistance becomes

If a wire conductor of 0.2 ohm resistance is doubled in length, its resistance becomes A) 0.2 ohm B) 0.4 ohm C) 0.8 ohm D) 1.6 ohm Sho...

## A 3 ohm resistor having 2 A current will dissipate the power of

A 3 ohm resistor having 2 A current will dissipate the power of A) 3 watts B) 6 watts C) 12 watts D) 24 watts Show Answer Ans: C) 1...

## The filament of an electric bulb is made of

The filament of an electric bulb is made of A) Carbon B) Aluminium C) Tungsten D) Nickel Show Answer Ans: C) Tungsten "Show...

## The rating of a fuse wire is always expressed in

The rating of a fuse wire is always expressed in A) Ampere-hours B) Ampere-volts C) Watt D) Amperes Show Answer Ans: D) Amperes ...

## Varistors are

Varistors are A) Insulators B) Non-linear resistors C) Carbon resistors D) Resistors with zero temperature coefficient Show Answer A...

## Which one of the following does not have negative temperature co-efficient

Which one of the following does not have negative temperature co-efficient ? A) Aluminium B) Paper C) Rubber D) Mica Show Answer Ans...

## A resistance having rating 10 ohms, 10 W is likely to be a

A resistance having rating 10 ohms, 10 W is likely to be a A) Metallic resistor B) Carbon resistor C) Wire wound resistor D) Variable re...

## Which is the best conductor of electricity?

Which is the best conductor of electricity? A) Iron B) Silver C) Copper D) Carbon Show Answer Ans: B) Silver "Show Answer&q...

## Ohm’s law is not applicable to

Ohm’s law is not applicable to A) Vacuum tubes B) Carbon resistors C) High voltage circuits D) Circuits with low current densities Sho...

## Which of the following materials has a negative temperature co-efficient of resistance?

Which of the following materials has a negative temperature co-efficient of resistance? A) Copper B) Brass C) Carbon D) Aluminum Show ...

## You have to replace 1500 ohm resistor in radio. You have no 1500 ohm resistor but have several 1000 ohm ones which you would connect

You have to replace 1500 ohm resistor in radio. You have no 1500 ohm resistor but have several 1000 ohm ones which you would connect A) Two...

## Which of the following material has nearly zero temperature co-efficient of resistance?

Which of the following material has nearly zero temperature co-efficient of resistance? A) Manganin B) Porcelain C) Carbon D) Copper S...

## Power factor consider in DC system?

No, Power factor doesn't consider in DC system. In a DC system, energy storing elements such as capacitors and inductors doesn’t consum...

## Four wires of same material, the same cross-sectional area and the same length when connected in parallel give a resistance of 0.25 Ohm. If the same four wires are connected is series the effective resistance will be

Four wires of same material, the same cross-sectional area and the same length when connected in parallel give a resistance of 0.25 Ohm. If ...

## The resistance of a parallel circuit consisting of two branches is 12 ohms. If the resistance of one branch is 18 ohms, what is the resistance of the other ?

The resistance of a parallel circuit consisting of two branches is 12 ohms. If the resistance of one branch is 18 ohms, what is the resistan...

## An instrument which detects electric current is known as

An instrument which detects electric current is known as A) Watt-meter B) Rheostat C) Voltmeter D) Galvanometer Show Answer Ans: D) ...

## Three resistances of 10 ohms, 15 ohms and 30 ohms are connected in parallel.The total resistance of the combination is

Three resistances of 10 ohms, 15 ohms and 30 ohms are connected in parallel.The total resistance of the combination is A) 5 ohms B) 10 ohm...

## With rise in temperature the resistance of semi-conductors

With rise in temperature the resistance of semi-conductors A) Increases B) Decreases C) First increases and then decreases D) Remains co...

## With rise in temperature the resistance of pure metals

With rise in temperature the resistance of pure metals A) Increases B) Decreases C) First increases and then decreases D) Remains consta...

## The resistance of a conductor varies inversely as

The resistance of a conductor varies inversely as A) Length B) Area of cross-section C) Temperature D) Resistivity Show Answer Ans:...

## When P = Power, V = Voltage, I = Current, R = Resistance and G = Conductance, which of the following relation is incorrect?

When P = Power, V = Voltage, I = Current, R = Resistance and G = Conductance, which of the following relation is incorrect? A) V = √ (PR) ...

## The unit of electrical conductivity is

The unit of electrical conductivity is A) mho / metre B) mho / sq. m C) ohm / metre D) ohm / sq. m Show Answer Ans: A) mho / metre ...

## Which of the following bulbs will have the least resistance ?

Which of the following bulbs will have the least resistance ? A) 220 V, 60 W B) 220 V, 100 W C) 115 V, 60 W D) 115 V, 100 W. Show Ans...

## The resistance of a 100 W, 200 V lamp is

The resistance of a 100 W, 200 V lamp is A) 100 ohm B) 200 ohm C) 300 ohm D) 400 ohm Show Answer Ans: D) 400 ohm "Show Answ...

## Cells are connected in parallel

Cells are connected in parallel... A) to increase internal resistance B) to increase current capacity C) to increase output voltage D) n...

## The capacity of a cell is measured in

The capacity of a cell is measured in.... A) ampere-hours B) ampere C) watts D) watt-hours Show Answer Ans: A) ampere-hours &quo...

## When full charged a cell (battery), the specific gravity of electrolyte is---

When full charged a cell (battery), the specific gravity of electrolyte is--- A) 1.0 B) 1.1 C) 1.2 D) 1.3 Show Answer Ans: D) 1.3 ...

## Sunday, May 26, 2019

## Electrolyte of lead acid battery is..

Electrolyte of lead acid battery is... A) HCL B) H 2 SO 4 C) ZnSo 4 D) None of above Show Answer Ans: B) H2SO4 "Show Answe...

## Which resistor will be physically larger in size...

Which resistor will be physically larger in size... A) 10 ohm, 50 watt B) 100 ohm, 10 watt C) 1000 ohm, 10 watt D) 10000 ohm, 10 watt ...

## Which is the lightest particle of atom?

Which is the lightest particle of atom? A) proton B) Electron C) Neutron D) All of above Show Answer Ans: B) Electron "Sho...

## Which of the following is not the unit of electrical power

Which of the following is not the unit of electrical power A) joule/second B) watt C) volt ampere D) volt/ampere Show Answer Ans: D)...

## Tow bulbs marked 200 watts - 250 V, and 100 watts - 250 V are joined in series to 250 V supply. The power consumed by the circuit is

Tow bulbs marked 200 watts - 250 V, and 100 watts - 250 V are joined in series to 250 V supply. The power consumed by the circuit is A)300 ...