1 Answer

Answer :

To avoid the effect of stray magnetic field in A.C. bridges we can use magnetic screening.

Related questions

Description : What arc the errors occurring in measuring devices due to stray magnetic field and temp '? Explain how to compensate them.

Last Answer : 1. Error due to stray magnetic fields-   Main magnetic field gets disturbed by external magnetic fields known as stray magnetic fields.  2. Compensation technique   To avoid this error, ... resistance alloy having a negligible resistance temp coefficient in the ratio of 1:10 for pressure coil 

Description : A magnetic circuit has effective iron length of 100 cm and it is wound with 800 turns of wire carries 1 A. Find the magnetic field strength.

Last Answer : magnetic field strength

Description : Derive an expression for energy stored in a magnetic field . 

Last Answer : Expression for energy stored in a magnetic field: The energy is stored in magnetic field when current increases and return back when the current decreases. At instant t' seconds after closer of switch ... energy absorbed by the magnetic field when current increases from 0 to I amperes 

Description : Define magnetic field strength and state its unit.

Last Answer : Magnetic field strength is the force experienced by a unit N-pole when placed at any point in a magnetic field is known as magnetic field strength or magnetizing force. Magnetising force or magnetic field ... unit of length is metre. So the unit of magnetic field strength is ampere turns per metre.

Description : Which of the following laws relates the magnetic field to the magnitude, direction, length, and proximity of the electric current? A) Lenz’s law B) Faraday’s law C) Biot–Savart law D) None of these

Last Answer : Which of the following laws relates the magnetic field to the magnitude, direction, length, and proximity of the electric current? A) Lenz’s law B) Faraday’s law C) Biot–Savart law D) None of these

Description : Which of the following statements is not characteristic of a static magnetic field? (A) It is solenoidal. (B) It is conservative. (C) It has no sinks or sources. (D) Flux lines are always closed.

Last Answer : Which of the following statements is not characteristic of a static magnetic field? (A) It is solenoidal. (B) It is conservative. (C) It has no sinks or sources. (D) Flux lines are always closed.

Description : How can a magnetic field be used to generate an electric current?

Last Answer : Magnetic  field  can  be  used  to  generate  electric  current  on  a  condition  that  it  is  on  a  rate  of  changing  magnetic  flux.  (Faraday's  law)

Last Answer : In a D.C. machine stray loss is the sum of iron loss and mechanical loss.

Description : What is the percentage of stray losses in DC machine?

Last Answer : Percentage of stray losses in DC machine is about 1 % .

Description : Are there any privately owned bridges in western democracies?

Last Answer : Of course there are! If you don’t believe it, look up the definitions for “bridge” and discover what can result from asking a vague question.

Description : An unshielded moving iron voltmeter is used to measure the voltage in an AC circuit. The stray DC magnetic field having a component along the axis will be  (1) unaffected (2) decreased (3) increased (4) either decreased or increased depending on the direction of the DC field

Last Answer : An unshielded moving iron voltmeter is used to measure the voltage in an AC circuit. The stray DC magnetic field having a component along the axis will be either decreased or increased depending on the direction of the DC field

Description : I want to find a general contractor who can build a pedestrian concrete bridge. Where can I find some?

Last Answer : Where are you? Who did the design (Professional Engineer) ? Who is going to use the bridge, city sidewalk traffic or mall?

Description : What is the longest bridge over a body water?

Last Answer : I can’t give you a correct answer on this because I really dont know but the longest bridge I know of is the Newport bridge in Rhode Island

Description : Define junction field effect transistor (JFET) and give an example.

Last Answer : Junction Field-Effect Transistor: It is a semiconductor device having three terminals, namely Gate, Drain and Source, in which the current flow is controlled by an electric field set up by an external voltage applied ... : i) n-channel JFET and ii) p-channel JFET Examples of JFET: BFW 10, BFW 11 

Description : Explain magnetic effect employed in measuring instrument.

Last Answer : Magnetic Effect:  I) In PMMC meters:  ➢ When a current is passed through a conductor, magnetic field is produced round the conductor. Due to this field when current ... field it experiences a mechanical force.  Examples: Electrodynamometer type instruments, Induction type instrument. 

Description : Explain hysteresis loss, eddy current loss and skin effect limitations with reference to magnetic material.

Last Answer : Hysteresis loss: Hysteresis loss is a loss which occurs due to the friction of magnetic domain due to the change in magnetic field in ferromagnetic material like iron. Hysteresis loss causes power loss ... loss in transformer is given by, We=Kef2Kf2Bm2watts Skin effect limitations:

Last Answer : In a shaded pole single-phase motor, the revolving field is produced by the use of shading coils.

Description : How to Kick a Football Field Goal

Last Answer : How to Kick a Football Field Goal There are only a few seconds left in the game, and one field goal attempt is all that stands between you and gridiron glory, or a place in the Hall of Shame. ... right kick for the right play, and get that game-winning field goal just right between the goal posts.

Description : How to Plow a Field

Last Answer : How to Plow a Field Civilization began when human beings started to turn over the soil to plant food. Plowing may have come a long way since the first human beings used their hands and ... budget. With these tools, you can plow fields and help contribute to the advancement of human civilization.

Description : How to Field Dress a Deer ?

Last Answer : How to Field Dress a Deer If you enjoy hunting deer, there's one important task you need to do before you can haul your prized catch back home: you'll need to field dress it. Field dressing ... you go hunting. Just follow these steps and you'll bring your prized catch home without any trouble.

Description : State advantages of rotating field type alternators. 

Last Answer : Advantages of Rotating Field Type Alternator: 1) For high-voltage alternator, large space is required to accommodate conductors with insulation, as high voltage is induced in them. If field poles are placed ... is kept rotating. 8) Rotating field is comparatively light and can run with high speed. 

Description :  Field intensity formula

Last Answer :  Field intensity formula

Description : Energy stored in electrostatic field of capacitance formula

Last Answer : Energy stored in electrostatic field of capacitance formula

Description : In a synchronous machine, if the field flux axis ahead of the armature field axis in the direction of rotation, the machine is operating as  (1) synchronous motor (2) synchronous generator (3) asynchronous motor (4) asynchronous generator

Last Answer : In a synchronous machine, if the field flux axis ahead of the armature field axis in the direction of rotation, the machine is operating as synchronous generator 

Description : The ability of materials to become polarized under an applied electric field is called _______ A) Ferroelectricity B) Paraelectricity C) Polectricity D) None of these

Last Answer : The ability of materials to become polarized under an applied electric field is called Paraelectricity

Description : The electric field inside a hollow conducting sphere ________ A) Depends on the diameter of the sphere  B) Varies according to the direction of earth’s magnetic poles C) Is zero  D) None of these

Last Answer : The electric field inside a hollow conducting sphere Is zero

Description : It is possible to increase the field flux and, at the same time, increase the speed of a d.c. motor provided its .......... is held constant.

Last Answer : It is possible to increase the field flux and, at the same time, increase the speed of a d.c. motor provided its armature current is held constant.

Description : A field of force can exist only between?

Last Answer : A field of force can exist only between two ions.

Description : A sinusoidal voltage of 5 Hz is applied to the field of a shunt generator. The armature voltage wave?

Last Answer : A sinusoidal voltage of 5 Hz is applied to the field of a shunt generator. The armature voltage wave will be of 5 Hz.

Last Answer : Flashing the field of D.C. generator means creating residual magnetism by a D.C. source.

Last Answer : If a D.C. shunt motor is working at full load and if shunt field circuit suddenly opens this will make armature to take heavy current, possibly burning it.

Last Answer : If the field of a D.C. shunt motor gets opened while motor is running the motor will attain dangerously high speed.

Last Answer : If the field winding of an unloaded salient pole synchronous motor is open circuited, the motor will stop.

Description : MOSFET uses the electric field of?

Last Answer : MOSFET uses the electric field of gate capacitance.

Description : An electric motor in which both stator field and rotor rotates with same speed is called?

Last Answer : An electric motor in which both stator field and rotor rotates with same speed is called synchronous motor.

Description : If the field of synchronous motor is under excited, power factor will be?

Last Answer : If the field of synchronous motor is under excited, power factor will be lagging.

Description : Is electric potential zero when electric field is zero?

Last Answer : Yes  .If  electric  field  is  zero  then  electric  potential  is  zero  ,  not  even  one.

Description : What is the direction of the induced electric field?

Last Answer : It  is  in  opposite  direction   to  the  one  that   produced  it.

Description : Can the electric field between two positive charges be zero?

Last Answer : It  can  only  if  they  have  equal  charges.

Description : What is the direction of the electric field?

Last Answer : Electric   field    is  at   right angle   widh  flow  of  current  (right  hand   rule).

Description : From which material field coils of DC generator are made of?

Last Answer : Field coils of DC generator are usually made of copper.

Description : Field control of DC motor

Last Answer : Field control of DC motor

Description : Magnetic circuit breakers use _________ A) Permanent magnets B) Earth magnets C) Solenoid D) All the above

Last Answer : Magnetic circuit breakers use Solenoid 

Last Answer : Yes, Induction heating is used for both magnetic and non-magnetic materials.

Description : How does a Magnetic Compass Work?

Last Answer : How does a Magnetic Compass Work? A compass is one of the simplest tools available, and is extremely practical. A compass is a device that shows the direction of north. Before GPS and other ... has to be allowed to move frictionlessly. Almost any resistance will stop the magnet from turning north.

Description : Magnetic and Non-magnetic Materials

Last Answer : We have now looked at a number of ways in which matter can be grouped, such as into metals, semi-metals and non-metals; electrical conductors and insulators, and thermal conductors and insulators. ... information must be stored, in computers and TV's, as well as in generators and electric motors.

Description : State the material used for making (1) Magnetic Core (2) Fuse element  

Last Answer : The material used for making of:  (1) Magnetic Core : Iron, cobalt, Nickel, CRGO, HRGO , silicon steel  (2) Fuse Element: Tin- lead wire, Tinned copper wire 

Description : Electro Magnetic Induction

Last Answer : Electro Magnetic Induction

Description : Explain with neat diagram series and parallel magnetic circuits. 

Last Answer : Series magnetic circuit: When different magnetic materials having different lengths, cross sectional areas and permeability are connected one after another, in which same flux is established in different sections, then it is called series ... flux, Φ = Φ1 + Φ2  Path 1: BAFE  Path 2: BACD