The emf induced in the primary of a transformer (A) is in phase with the flux. (B) lags behind the flux by 90 degree. (C) leads the flux by 90 degree. (D) is in phase opposition to that of flux.

The emf induced in the primary of a transformer
(A) is in phase with the flux. (B) lags behind the flux by 90 degree.
(C) leads the flux by 90 degree. (D) is in phase opposition to that of flux.
by

1 Answer

Answer :

(C) leads the flux by 90 degree.
by

Related questions

In a three phase transformer, if the primary side is connected in star and secondary side is connected in delta, what is the angle difference between phase voltage in the two cases. (A) delta side lags by -30°. (B) star side lags by -30°. (C) delta side leads by 30°. (D) star side leads by -30°.

Description : In a three phase transformer, if the primary side is connected in star and secondary side is connected in delta, what is the angle difference between phase voltage in the two cases. (A) delta side lags by -30°. (B) star side lags by -30°. (C) delta side leads by 30°. (D) star side leads by -30°.

Last Answer : Ans: C This is vector group and has +30° displacement. Therefore, delta side leads by +30°.

No load current in a transformer: (A) lags the applied voltage by 90° (B) lags the applied voltage by somewhat less than 90° (C) leads the applied voltage by 90° (D) leads the applied voltage by somewhat less than 90°

Description : No load current in a transformer: (A) lags the applied voltage by 90° (B) lags the applied voltage by somewhat less than 90° (C) leads the applied voltage by 90° (D) leads the applied voltage by somewhat less than 90°

Last Answer : Ans: B The primary input current under no load conditions has to supply (i) iron losses in the core i.e hysteresis loss and eddy current loss (ii) a very small amount of Cu loss in the primary (there being no Cu loss in secondary as it is open)

6 In a two winding transformer, the primary and secondary induced emf E1 & E2 are always A. equal in magnitude B. anti phase with each other C. in phase with each other D. determined by load on transformer secondary

Description : 6 In a two winding transformer, the primary and secondary induced emf E1 & E2 are always A. equal in magnitude B. anti phase with each other C. in phase with each other D. determined by load on transformer secondary

Last Answer : C. In phase with each other

The velocity vector in a vector diagram for a harmonic motion A Lags the displacement vector by 180 0 B Lags the displacement vector by 90 0 C Leads the displacement vector by 90 0 D Leads the displacement vector by 180 0

Description : The velocity vector in a vector diagram for a harmonic motion A Lags the displacement vector by 180 0 B Lags the displacement vector by 90 0 C Leads the displacement vector by 90 0 D Leads the displacement vector by 180 0

Last Answer : C Leads the displacement vector by 90 0

The velocity vector in a vector diagram for a harmonic motion A Lags the displacement vector by 180 0 B Lags the displacement vector by 90 0 C Leads the displacement vector by 90 0 D Leads the displacement vector by 180 0

Description : The velocity vector in a vector diagram for a harmonic motion A Lags the displacement vector by 180 0 B Lags the displacement vector by 90 0 C Leads the displacement vector by 90 0 D Leads the displacement vector by 180 0

Last Answer : C Leads the displacement vector by 90 0

The velocity vector in a vector diagram for a harmonic motion C (A) Lags the displacement vector by 180 0 (B) Lags the displacement vector by 90 0 (C) Leads the displacement vector by 90 0 (D) Leads the displacement vector by 180 0

Description : The velocity vector in a vector diagram for a harmonic motion C (A) Lags the displacement vector by 180 0 (B) Lags the displacement vector by 90 0 (C) Leads the displacement vector by 90 0 (D) Leads the displacement vector by 180 0

Last Answer : (C) Leads the displacement vector by 90 0

28.In a two winding transformer, the emf /turn in secondary winding is always......the induced emf power turn in primary A. equal to k times B. equal to 1/k times C. equal D. greater than

Description : 28.In a two winding transformer, the emf /turn in secondary winding is always......the induced emf power turn in primary A. equal to k times B. equal to 1/k times C. equal D. greater than

Last Answer : C. equal

The no load current in a transformer lags behind the applied voltage by an angle of about?

Last Answer : The no load current in a transformer lags behind the applied voltage by an angle of about 75°.

The current in ampere through an inductor is i(10+20t) Here t is in second. The induced emf in the inductor 4V. Total flux linked with the inductor at

Description : The current in ampere through an inductor is i(10+20t) Here t is in second. The induced emf in the inductor 4V. Total flux linked with the inductor at

Last Answer : The current in ampere through an inductor is i(10+20t) Here t is in second. The induced emf in the inductor 4V. ... 10 Wb B. 20 Wb C. 30 Wb D. 40 Wb

Find the emf induced in a coil of 60 turns with a flux rate of 3 units. a) -60 b) -180 c) 60 d) 180

Description : Find the emf induced in a coil of 60 turns with a flux rate of 3 units. a) -60 b) -180 c) 60 d) 180

Last Answer : b) -180

The induced emf in a material opposes the flux producing it. This is a) Faraday law b) Ampere law c) Lenz law d) Curie law

Description : The induced emf in a material opposes the flux producing it. This is a) Faraday law b) Ampere law c) Lenz law d) Curie law

Last Answer : c) Lenz law

Which of the following will produce an induced emf: a. Changing area of coil b. Changing magnetic flux c. changing orientation of coil d. all of them

Description : Which of the following will produce an induced emf: a. Changing area of coil b. Changing magnetic flux c. changing orientation of coil d. all of them

Last Answer : c. changing orientation of coil

The current flowing in a coil due to induced emf depends upon: a. shape of coil b. resistance of coil c. area of coil d. magnetic flux

Description : The current flowing in a coil due to induced emf depends upon: a. shape of coil b. resistance of coil c. area of coil d. magnetic flux

Last Answer : a. shape of coil

The induced emf is produced in a circuit due to: a. Initial magnetic flux b. final magnetic flux c. Change of magnetic flux d. constant magnetic flux

Description : The induced emf is produced in a circuit due to: a. Initial magnetic flux b. final magnetic flux c. Change of magnetic flux d. constant magnetic flux

Last Answer : d. constant magnetic flux

When a conductor cuts magnetic flux, an emf is induced in the conductor. This is known as...

Description : When a conductor cuts magnetic flux, an emf is induced in the conductor. This is known as  (a) Joule's law (b) Faraday's law (c) Coulomb's law (d) Ampere’s law

Last Answer : When a conductor cuts magnetic flux, an emf is induced in the conductor. This is known as Faraday's law. There are two Faraday's law of electromagnetic induction. 1. Changing flux produces emf ... 2. Magnitude of induced e.m.f. is directly proportional to rate of change of flux linkage.

The electrical schematic illustrated in figure A, depicts a/an _____________. EL-0059 A. autotransformer B. Delta Wye transformer C. primary EMF generator D. potential transformer

Description : The electrical schematic illustrated in figure A, depicts a/an _____________. EL-0059 A. autotransformer B. Delta Wye transformer C. primary EMF generator D. potential transformer

Last Answer : Answer: D

The greatest induced EMF will occur in a straight wire moving at constant speed through a uniform magnetic field when the angle between the direction of the wire's motion and the direction of the magnetic field is w) 0 degrees x) 30 degrees y) 60 degrees z) 90 degrees

Description : The greatest induced EMF will occur in a straight wire moving at constant speed through a uniform magnetic field when the angle between the direction of the wire's motion and the direction of the magnetic field is w) 0 degrees x) 30 degrees y) 60 degrees z) 90 degrees

Last Answer : ANSWER: Z -- 90 DEGREES

The response of a damped forced vibration system A) Leads the system excitation ( for all values of ω/ ωn) B) Lags the system excitation ( for all values of ω/ ωn) C) Leads the system excitation ( for all values of ω/ ωn << 1)

Description : The response of a damped forced vibration system A) Leads the system excitation ( for all values of ω/ ωn) B) Lags the system excitation ( for all values of ω/ ωn) C) Leads the system excitation ( for all values of ω/ ωn

Last Answer : B) Lags the system excitation ( for all values of ω/ ωn)

The vector representing acceleration on a vector diagram for a harmonic motion A) Lags the displacement vector by 90° B) Lags the displacement vector by 180° C) Leads the displacement vector by 90° D) Leads the displacement vector by 180°

Description : The vector representing acceleration on a vector diagram for a harmonic motion A) Lags the displacement vector by 90° B) Lags the displacement vector by 180° C) Leads the displacement vector by 90° D) Leads the displacement vector by 180°

Last Answer : C) Leads the displacement vector by 90°

The velocity vector in a vector diagram for a harmonic motion A) Lags the displacement vector by 180° B) Leads the displacement vector by 90° C) Lags the displacement vector by 90° D) Leads the displacement vector by 180°

Description : The velocity vector in a vector diagram for a harmonic motion A) Lags the displacement vector by 180° B) Leads the displacement vector by 90° C) Lags the displacement vector by 90° D) Leads the displacement vector by 180°

Last Answer : B) Leads the displacement vector by 90°

In cables the charging current (a) lags the voltage by 90° (b) leads the voltage by 90° (c) lags the voltage by 180° (d) leads the voltage by 180°

Description : In cables the charging current (a) lags the voltage by 90° (b) leads the voltage by 90° (c) lags the voltage by 180° (d) leads the voltage by 180°

Last Answer : (b) leads the voltage by 90°

6 The value of flux involved in the emf equation of a transformer is A. rms value B. rms value C. Maximum value D. Instantaneous value

Description : 6 The value of flux involved in the emf equation of a transformer is A. rms value B. rms value C. Maximum value D. Instantaneous value

Last Answer : C) maximum value

Write down the equation for frequency of emf induced in an Altenator.

Description : Write down the equation for frequency of emf induced in an Altenator.

Last Answer : F = (PN)/120 Hz,Where P- Number of poles, N-Speed in rpm

What is the equation used to find out frequency of number of cycles of induced emf?

Description : What is the equation used to find out frequency of number of cycles of induced emf?

Last Answer : f = NP/120

How we can find the direction of induced emf?

Description : How we can find the direction of induced emf? 

Last Answer : The direction of induced emf can be find out by the Fleming's right hand rule', and lenz's law' Fleming's right hand rule : Fleming's right hand rule states that, if ... that the action of magnetic field set up by induced current tends to opposes the root cause which produces it. 

Slip of the induction machine is 0.02 and the stator supply frequency is 50 Hz. What will be the frequency of the rotor induced emf? (A) 10 Hz. (B) 50 Hz. (C) 1 Hz. (D) 2500 Hz.

Description : Slip of the induction machine is 0.02 and the stator supply frequency is 50 Hz. What will be the frequency of the rotor induced emf? (A) 10 Hz. (B) 50 Hz. (C) 1 Hz. (D) 2500 Hz.

Last Answer : Ans: C Given : s = 0.02 ; f = 50 Hz Therefore, frequency of rotor induced emf = s f = 0.02 x 50 = 1.0 Hz

A 4 pole lap wound dc shunt motor rotates at the speed of 1500 rpm, has a flux of 0.4 mWb and the total number of conductors are 1000. What is the value of emf? (A) 100 Volts. (B) 0.1 Volts. (C) 1 Volts. (D) 10 Volts.

Description : A 4 pole lap wound dc shunt motor rotates at the speed of 1500 rpm, has a flux of 0.4 mWb and the total number of conductors are 1000. What is the value of emf? (A) 100 Volts. (B) 0.1 Volts. (C) 1 Volts. (D) 10 Volts.

Last Answer : Ans: D Given N = 1500 rpm, Φ = 0.4 mWb, Z = 1000, P = 4, & A= 4 Therefore, Eb = NΦPZ / 60 A = 1500 x 0.4 x 4 x 1000 x 10^-3 / 60 x 4 = 60/6 = 10 volts

The induced current in transformer which produced in the direction perpendicular to flux, is known as: a. Conventional current b. electronic current c. Perpendicular current d. Eddy current

Description : The induced current in transformer which produced in the direction perpendicular to flux, is known as: a. Conventional current b. electronic current c. Perpendicular current d. Eddy current

Last Answer : c. Perpendicular current

The introduction of interpoles in between the main pole improves the performance of d.c. machines, because (A) The interpole produces additional flux to augment the developed torque. (B) The flux waveform is improved with reduction in harmonics. (C) The inequality of air flux on the top and bottom halves of armature is removed. (D) A counter e.m.f. is induced in the coil undergoing commutation.

Description : The introduction of interpoles in between the main pole improves the performance of d.c. machines, because (A) The interpole produces additional flux to augment the developed torque. (B) The flux waveform is ... armature is removed. (D) A counter e.m.f. is induced in the coil undergoing commutation.

Last Answer : Ans: D Counter e.m.f is produced, it neutralizes the reactive emf.

(a) Define permeability. (b) Define MMF. (c) Define form factor of an alternating quantity. (d) Define frequency and time period of an alternating quality. (e) Define transformation ratio of transformer. (f) State the EMF equation of a 1 transformer and state the meaning of each term used. (g) Give two applications of single phase motors.

Description : (a) Define permeability. (b) Define MMF. (c) Define form factor of an alternating quantity. (d) Define frequency and time period of an alternating quality. (e) Define transformation ratio of transformer. ... and state the meaning of each term used. (g) Give two applications of single phase motors. 

Last Answer : Permeability : It is the ability of a magnetic/Non magnetic material to allow setting up of flux in it.  MMF : The magneto motive force (MMF) is the force required to setup flux in a magnetic / ... applications of single phase motors : Water pumps, ceiling fan, lathe machine

EMF equation of the transformer?

Description : EMF equation of the transformer?

Last Answer : A. E = 4.44ΦmfN Volts. If E1 & E2 are primary and secondary emf’s and N1 & N2 are primary and secondary turns then, Voltage ratio= E1/E2 and Turns ratio of transformer = N1/N2 E1/E2 = N1/N2

What is the EMF equation of transformer?

Description : What is the EMF equation of transformer?

Last Answer : Erms = 4.44 f Φ maxT volt

What is the emf equation for transformer?

Description : What is the emf equation for transformer?

Last Answer : Always maximum flux reaches from zero to maximum in one quarter of the cycle. That is in of second. That is equal to 1/200 second. Average rate of change of flux = Qm / f. = Qm * 4 * f. = 4 f Qm Weber / ... * form factor. ∴ rms. Value of emf = 1.11 * 4 f Qm N volts. = 4.44 f Qm N volts.

The emf of a primary cell depends upon the: a) Physical dimension of the cell b) Nature of the electrolyte c) Nature of the electrode d) Both (b) and (c)

Description : The emf of a primary cell depends upon the: a) Physical dimension of the cell b) Nature of the electrolyte c) Nature of the electrode d) Both (b) and (c)

Last Answer : Ans: D

Which of the following statements describes what will occur if the motor shown in the illustration is required to carry 150% of full load? EL-0056 A. The primary counter emf will be increased. B. The stator current will increase. C. The slip will decrease. D. The slip value, stator current curve, and torque curve will all coincide.

Description : Which of the following statements describes what will occur if the motor shown in the illustration is required to carry 150% of full load? EL-0056 A. The primary counter emf will be increased. B. ... slip will decrease. D. The slip value, stator current curve, and torque curve will all coincide.

Last Answer : Answer: B

In transformer, alternating current is induced inA. primary coilB. secondary coilC. iron coreD. resistor

Description : In transformer, alternating current is induced inA. primary coil B. secondary coil C. iron core D. resistor

Last Answer : primary coil

The e.m.f. induced in the primary of a transformer: ...

Description : The e.m.f. induced in the primary of a transformer:  (A) is in phase with the flux (B) lags behind the flux by 90 degree (C) leads the flux by 90 degree (D) is in phase opposition to that of flux

Last Answer : The e.m.f. induced in the primary of a transformer: leads the flux by 90 degree 

The leads to the primary and the high-voltage secondary windings of a power transformer usually are of what color?

Description : The leads to the primary and the high-voltage secondary windings of a power transformer usually are of what color?

Last Answer : Primary leads-black; secondary leads red.

What is primary leakage flux in transformer ?

Description : What is primary leakage flux in transformer ?

Last Answer : The leakage flux caused by the magnetomotive force ( mmf) due to the primary ampere turn is called primary leakage flux when it produces a leakage path from the primary winding. This was the second ... answer regarding Transformer. I will appear with the 3rd episode in the future. So stay with us.

38] In a transformer the energy is conveyed from primary to secondary? A. Through cooling coil B. Through air C. By the flux D. None of the above

Description : 38] In a transformer the energy is conveyed from primary to secondary? A. Through cooling coil B. Through air C. By the flux D. None of the above

Last Answer : C. By the flux

12] Which is not the basic element of the transformer? A. core B. primary winding C. secondary winding D. mutual flux

Description : 12] Which is not the basic element of the transformer? A. core B. primary winding C. secondary winding D. mutual flux

Last Answer : D. Mutual flux

In the illustrated circuit, if the input to leads 'B' and 'Y' was 24 VDC the output between 'A' and 'X' will be _________. EL-0069 A. 24 VDC B. 22.8 VDC, 24 VDC minus the 1.2 VDC voltage drop across two diodes C. undeterminable without knowing the turns ratio of the transformer D. 0 VDC

Description : In the illustrated circuit, if the input to leads 'B' and 'Y' was 24 VDC the output between 'A' and 'X' will be _________. EL-0069 A. 24 VDC B. 22.8 VDC, 24 VDC minus the 1.2 VDC voltage drop across two diodes C. undeterminable without knowing the turns ratio of the transformer D. 0 VDC

Last Answer : Answer: D

In replacing a defective transformer with a new one, which of the following actions must be carried out to insure proper operation of the equipment it serves? A. The secondary leads must be grounded for 10 minutes to remove static charges. B. The transformer connections must be made as before with regard to the indicated polarity. C. The iron core of the transformer must be flashed to pre-magnetize it. D. The iron core must be grounded for 10 minutes to remove any residual magnetism.

Description : In replacing a defective transformer with a new one, which of the following actions must be carried out to insure proper operation of the equipment it serves? A. The secondary leads must be grounded ... magnetize it. D. The iron core must be grounded for 10 minutes to remove any residual magnetism.

Last Answer : Answer: B

Transformer cores are laminated to reduce _____________. A. eddy currents B. secondary flux C. leakage flux D. all of the above

Description : Transformer cores are laminated to reduce _____________. A. eddy currents B. secondary flux C. leakage flux D. all of the above

Last Answer : Answer: A

The current in ampere through an inductor is i(10+20t) Here t is in second. The induced emf in the inductor 4V. The self inductance of the indicator i

Description : The current in ampere through an inductor is i(10+20t) Here t is in second. The induced emf in the inductor 4V. The self inductance of the indicator i

Last Answer : The current in ampere through an inductor is i(10+20t) Here t is in second. The induced emf in the inductor 4V. The ... B. `0.4` C. `0.1` D. `1.0`

On what factors does the induced emf in the coil depend?

Description : On what factors does the induced emf in the coil depend?

Last Answer : Induced e.m.f in a coil increases with increase in: a) the number of turns of the coil, b) the strength of the magnetic field c) the speed with which the magnet or the coil moves d) area of the coil

Find the induced EMF in an inductor of 2mH and the current rate is 2000 units. a) 4 b) -4 c) 1 d) -1

Description : Find the induced EMF in an inductor of 2mH and the current rate is 2000 units. a) 4 b) -4 c) 1 d) -1

Last Answer : b) -4

What is meant by induced emf? By counter emf?

Description : What is meant by induced emf? By counter emf?

Last Answer : Induced emf is the emf which appears across a conductor when there is relative motion between the conductor and a magnetic field; counter emf is the emf induced in a conductor that opposes the applied voltage.

Why is no emf induced in a rotating coil when it passes through the neutral plane?

Description : Why is no emf induced in a rotating coil when it passes through the neutral plane?

Last Answer : No flux lines are cut.

What rule should you use to determine the direction of induced emf in a coil?

Description : What rule should you use to determine the direction of induced emf in a coil?

Last Answer : The left-hand rule for generators.