1 Answer

Answer :

If B is the flux density, I the length of conductor and v the velocity of conductor, then induced e.m.f. is given by Blv.

Related questions

Description : In an induction motor if the flux density is reduced to one-half, of its normal value then the torque will  (1) reduce to one-half (2) reduce to one-fourth (3) remain unchanged (4) increase four times

Last Answer : In an induction motor if the flux density is reduced.to one-half, of its normal value then the torque will reduce to one-fourth

Last Answer : When the armature of a D.C. motor rotates, e.m.f. induced is back e.m.f.

Description : Flux density formula

Last Answer : Flux density formula

Description : Define the following terms: i) Magnetic flux density, ii) Reluctance, iii) Magneto-motive force, iv) Permeance.

Last Answer : (i) Magnetic flux density (B): It is the magnetic flux per unit area measured at right angles to the flux path. (Its unit is weber/m2 or tesla).  (ii) Reluctance: It is the ... flux to set up through it and it is reciprocal of reluctance. Permeance = 1/ Reluctance. Unit: weber/ampere.

Description : Define magnetic flux density and state its formula.

Last Answer : The magnetic flux per unit area is called as magnetic flux density. Magnetic flux density is denoted by B. The formula for magnetic flux density is Weber per metre square or Tesla. Mathematically ... the unit of magnetic flux density is Weber per metre square which is also called as Tesla.

Description : What is the permissible flux density in case of cold rolled grained oriented steel?

Last Answer : The permissible flux density in case of cold rolled grained oriented steel is 1.7 Wb/m2.

Last Answer : Flux density is denoted by B. And it is given as B = flux/ area Where, the unit of flux is Weber and unit of area is meter square. So the unit of flux density is weber per meter square which is also called as Tesla.

Description : Explain dynamic and static induced emf with neat diagram.

Last Answer : Dynamically Induced EMF:-  In this case, either coil moves or magnet moves, so that there is relative motion between coil & magnetic field. Thus magnetic field is cut by coil & emf is induced in it. The emf ... The expression for induced EMF is e= -L(di/dt) or = -N(dϕ/dt).

Description : Self induced emf and Mutually induced emf

Last Answer : (i) Self-induced e.m.f.: The e.m.f. induced in a coil due to the change of its own flux linked with it, is called self-induced e.m.f.  (ii) Mutually induced e.m.f.: The e.m.f. induced in a coil due to the changing current in the neighbouring coil, is called mutually induced e.m.f. 

Description : Compare statically induced emf with dynamically induced emf on any four points.

Last Answer : Statically induced emf Dynamically induced emf Emf is induced without any relative motion between conductor and magnetic field. Emf is induced due to relative motion between conductor ... induced in transformer windings e.g emf induced in Generator, Alternator armature windings

Description : Define: 1) statically induced EMF 2) dynamically induced EMF Write the names of equipments in which these two types of EMF get induced

Last Answer : Concept of statically induced emf: The emf induced in coil or conductors without any relative motion between it and magnetic field is called statically induced emf. When conductor is stationary and flux ... it. This emf is dynamically induced emf. e.g. Emf induced in generators, alternator.

Description : List the two types of induced EMF.

Last Answer : There are two types of EMF one is statically induced EMF and second is dynamically induced EMF.

Description : The induced emf in the armature of a lap -wound four -pole dc machine having 100 armature conductors rotating at 600 rpm and with 1 Wb flux per pole is  (1) 1000V (2) 100V (3) 600V (4) 10,000V

Last Answer : The induced emf in the armature of a lap -wound four -pole dc machine having 100 armature conductors rotating at 600 rpm and with 1 Wb flux per pole is 1000V

Last Answer : Interpole flux should be sufficient to neutralise both the armature reaction flux as well as commutating e.m.f. induced in the coil.

Description :  An energy signal has G(f) = 20. Its energy density spectrum is A) 20 B) 100 C) 400 D) 800  

Last Answer : 400

Description : If a wire conductor of 0.2 ohm resistance is doubled in length, its resistance becomes?

Last Answer : If a wire conductor of 0.2 ohm resistance is doubled in length, its resistance becomes 0.4 ohm.

Description : Self induced voltage across an inductance

Last Answer : Self induced voltage across an inductance

Description : Define natural, mechanical, forced and induced draught systems.

Last Answer : Natural draught system: - When the fuel is burnt (combustion) in the furnace due to natural circulation of air, the draught is called natural draught. Mechanical draught system: -  In a mechanical ... combustion. OR If fan/blower is placed after the furnace then it is called as induced draught

Description : How can we increase the induced current?

Last Answer : Induced  current  can  be  increased by  reducing  no  of   windings  on  the  secondary  part   compared   to   primary.

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

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

Description : A straight wire of length 0.20 m moves at a steady speed of 3.0 m s-1 at right angles to the magnetic field of flux density 0.10 T. The e.m.f induced across ends of wire is A. 0.5 V B. 0.06 V C. 0.05 V D. 0.04 V

Last Answer : 0.06 V

Description : Define the following terms and state their units: (i) Luminous intensity, (ii) Luminous flux

Last Answer : i) Luminous intensity: This is defined as the luminous flux emitted into a solid angle of space in a specific direction. Its unit is the candela.  OR  The luminous flux per unit solid angle ( ... energy radiated by the light source in all direction. The unit of luminous flux is lumen (lm) 

Description : Describe the concept of leakage flux, useful flux and fringing with neat diagram.

Last Answer : Leakage Flux

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 : Which of the following is a unit of magnetic flux? A) Weber B) Maxwell C) Both A and B D) None of these

Last Answer : Which of the following is a unit of magnetic flux? A) Weber B) Maxwell C) Both A and B D) None of these

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 : The property of a material which opposes the creation of magnetic flux in it is known as?

Last Answer : The property of a material which opposes the creation of magnetic flux in it is known as reluctance.

Description : The unit of magnetic flux is?

Last Answer : The unit of magnetic flux is weber.

Description : The path of magnetic flux in a transformer should have?

Last Answer : The path of magnetic flux in a transformer should have low reluctance.

Description : The counter e.m.f. of a d.c. motor?

Last Answer : The counter e.m.f. of a d.c. motor helps in energy conversion.

Last Answer : E.m.f. of a Weston cell is accurately measured by electrostatic voltmeter.

Last Answer : It is required to measure the true open circuit e.m.f. of a battery. The best device is D.C. potentiometer.

Last Answer : The mechanical power developed by a shunt motor will be maximum when the ratio of back e.m.f. to applied voltage is 0.5.

Last Answer : In case of D.C. shunt motors the speed is dependent on back e.m.f. only because flux is practically constant in D:C. shunt motors.

Last Answer : The armature may burn if the back e.m.f. of a D.C. motor vanishes suddenly.

Description : In lead acid battery the density of acid indicates the  (1) charge of the battery (2) level of acid (3) e.m.f of the battery (4) damage of the plates

Last Answer : In lead acid battery the density of acid indicates the charge of the battery

Description : Explain the suitability of aluminium as an electrical conductor with respect to its mechanical and electrical properties. 

Last Answer : Following are requirements of conductor:- i) High conductivity :  Material should have high conductivity, So that * cross section of conductor (size) reduces, * Copper losses reduces, * So Efficiency ... . Boiling point is 1820°C 9. Specific gravity is 2.7 10. High resistance to corrosion. 

Description : State properties of conductor material used for overhead conductor. 

Last Answer : Following are the properties of conductor material:-   1. High conductivity :- Material should have high conductivity 2. High mechanical strength:- Material should have sufficiently high mechanical strength ... available & less costly. 9. Scrap Value: - Material should have high scrap value. 

Last Answer : Which allows the flow electrons 

Description : reasons the transposition of conductor

Last Answer : Following reasons the transposition of conductor:  1. Due transposition of conductor inductance of each line is same LA = LB = LC, So drop due to inductive reactance in each line is same so ... interferences are less due to transposition.  Figure of transposition of conductor: 

Description : What is difference between Conductor and insulator ?

Last Answer : Conductor is a material that offers no resistance to the flow of current, while an insulator is a material that offers total resistance to the flows of current, It doesn't allowed any flows of current.

Description : Which is the best conductor: silver, carbon, or iron?

Last Answer : Silver is the best conductor. Carbon is the semiconductor. Iron have less conductance as compared to silver.

Description : How does the resistance of a conductor compare to that of an insulator?

Last Answer : The resistance of a conductor can be significantly lower than the resistance of an insulator, depending on each material's atomic properties.

Description : In a metal conductor, what is a free electron?

Last Answer :  When many atoms are close together in a copper wire, the outermost orbital electron of each copper atom can easily break free from its home or parent atom. These electrons then can migrate easily ... random. Such electrons that can move freely from one atom to the next are called free electrons.

Description : A 3 layer, total diameter of an ACSR conductor is 5 cm. Find the diameter of each strand?

Last Answer : A 3 layer, total diameter of an ACSR conductor is 5 cm. Find the diameter of each strand? 1 cm

Description : lf the wire which is vertical to this page has electron flow downwards the conductor will have

Last Answer : lf the wire which is vertical to this page has electron flow downwards the conductor will have a counter-clockwise field in the plane of the paper

Description : When electric current passes through a metallic conductor, its temperature rises. This is due to?

Last Answer : When electric current passes through a metallic conductor, its temperature rises. This is due to collisions between conduction electrons and atoms.

Description : The thickness of insulation provided on the conductor depends on?

Last Answer : The thickness of insulation provided on the conductor depends on the magnitude of voltage on the conductor.

Description : The insulation on a current carrying conductor is provided?

Last Answer : The insulation on a current carrying conductor is provided to prevent leakage of current, to prevent shock.

Description : Heat in a conductor is produced on the passage of electric current due to?

Last Answer : Heat  in  a   conductor  is  produced   due  to  frictional  collision  of  electrons   flow  as  they  conduct  current.