Updated Electromagnetism MCQs ( Electrical Engineering ) MCQs – Electrical Engineering MCQs
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Latest Electrical Engineering MCQs
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Latest Electromagnetism MCQs ( Electrical Engineering ) Mcqs
The most occurred mcqs of Electromagnetism MCQs ( Electrical Engineering ) in past papers. Past papers of Electromagnetism MCQs ( Electrical Engineering ) Mcqs. Past papers of Electromagnetism MCQs ( Electrical Engineering ) Mcqs . Mcqs are the necessary part of any competitive / job related exams. The Mcqs having specific numbers in any written test. It is therefore everyone have to learn / remember the related Electromagnetism MCQs ( Electrical Engineering ) Mcqs. The Important series of Electromagnetism MCQs ( Electrical Engineering ) Mcqs are given below:
Magnetic Field
1. What is the magnetic field outside a solenoid?
a) Infinity
b) Half the value of the field inside
c) Double the value of the field inside
d) Zero
Answer: d
Explanation: There are no magnetic lines of force outside a solenoid, hence the magnetic field outside a solenoid is zero.
2. Which, among the following qualities, is not affected by the magnetic field?
a) Moving charge
b) Change in magnetic flux
c) Current flowing in a conductor
d) Stationary charge
Answer: d
Explanation: A stationary charge is not affected by a magnetic field because stationary charges do not have any velocity. Magnetic field cannot occur in a particle having zero velocity.
3. When a charged particle moves at right angles to the magnetic field, the variable quantity is?
a) Momentum
b) Speed
c) Energy
d) Moment of inertia
Answer: a
Explanation: When a charged particle moves perpendicular to the field, its speed remains the same whereas its velocity keeps on changing. Momentum is the product of the mass of the particle and the velocity if the particle, hence since velocity varies, momentum also varies.
4. If the flow of electric current is parallel to the magnetic field, the force will be ______
a) Zero
b) Infinity
c) Maximum
d) Half the original value
Answer: a
Explanation: Force is a cross product. A cross product involves the sine of the angle between them. If two quantities are parallel to each other, the angle between them is zero. Sin(0) is zero, hence force is zero.
5. The ratio of magnetic force to electric force on a charged particle getting undeflected in a field is?
a) 1
b) 0
c) 2
d) 4
Answer: a
Explanation: When a charged particle is undeflected in a field, the magnitude of the magnetic force and electric force acting on the particle is the same, hence the ratio is 1.
6. What is the strength of magnetic field known as ________
a) Flux
b) Density
c) Magnetic strength
d) Magnetic flux density
Answer: d
Explanation: Strength of magnetic field is also known as magnetic flux density. It is the amount of magnetic field lines crossing unit area.
7. Weakest force in nature is?
a) Electric force
b) Gravitational force
c) Weak force
d) Magnetic force
Answer: b
Explanation: Gravitational force is the weakest force in nature as it does not bind anything strongly with its help.
8. How can a magnetic field be produced?
a) Using a permanent magnet
b) Electric current
c) Using a temporary magnet
d) Using a permanent magnet or electric current
Answer: d
Explanation: An electric current as well as the permanent magnet produces a magnetic field whereas a temporary magnet fails to do so.
9. Can we see magnetic flux lines?
a) Yes
b) No
c) Depends on the strength of the field
d) Only when the field strength is very large
Answer: b
Explanation: No, we cannot see magnetic flux lines as the “lines of magnetic flux” is purely an imaginary concept to understand the magnetic field clearly.
10. Magnetic Field lines move from _______
a) North to south
b) South to north
c) West to east
d) East to west
Answer: a
Explanation: Magnetic field lines originate at the north pole and terminate at the south pole of the magnet.
Direction of Magnetic Field
1. Field lines move from __________
a) North to south
b) South to north
c) West to east
d) East to west
Answer: a
Explanation: Magnetic field lines originate at the north pole and terminate at the south pole of the magnet.
2. Magnetic field lines ___________ at the north pole.
a) Emerge
b) Converge
c) Neither emerge nor converge
d) Either emerge or converge
Answer: a
Explanation: Magnetic field lines emerge at the north pole. Field lines seem to emerge at the north pole because they originate at the north pole.
3. Magnetic field lines ___________ at the south pole.
a) Emerge
b) Converge
c) Neither emerge nor converge
d) Either emerge or converge
Answer: b
Explanation: Magnetic field lines converge at the south pole. Field lines seem to converge at the south pole because they end at the south pole.
4. Which of the following is used to determine the direction of magnetic field in a current carrying conductor?
a) Left hand thumb rule
b) Right hand thumb rule
c) Right hand palm rule
d) Left hand palm rule
Answer: b
Explanation: The right hand thumb rule determines the direction of a magnetic field in a current carrying conductor. The rule states that when we align our right thumb in the direction of the current and curl our fingers around it, the direction of our fingers is the direction of the magnetic field.
5. According to Flemming’s left hand rule, the index finger denotes?
a) Direction of magnetic field
b) Direction of current
c) Direction of force
d) Direction of force as well as current
Answer: a
Explanation: According to Flemming’s left hand rule, the index finger denotes the direction of the magnetic field, the thumb denoted the direction of force and the middle finger denoted the direction of the current.
6. According to Flemming’s left hand rule, the middle finger denotes?
a) Direction of magnetic field
b) Direction of current
c) Direction of force
d) Direction of force as well as current
Answer: b
Explanation: According to Flemming’s left hand rule, the index finger denotes the direction of the magnetic field, the thumb denoted the direction of force and the middle finger denoted the direction of the current.
7. According to Flemming’s left hand rule, the thumb denotes?
a) Direction of magnetic field
b) Direction of current
c) Direction of force
d) Direction of force as well as current
Answer: c
Explanation: According to Flemming’s left hand rule, the index finger denotes the direction of the magnetic field, the thumb denoted the direction of force and the middle finger denoted the direction of the current.
8. The relation between the direction of force and the direction of magnetic field is _________
a) Same direction
b) Opposite direction
c) Perpendicular
d) Unrelated
Answer: c
Explanation: When a conductor carries a certain value of current, the force developed in the conductor, the current in the conductor and the magnetic field in the conductor are mutually perpendicular to each other.
9. The relation between the direction of current and the direction of magnetic field is ________
a) Same direction
b) Opposite direction
c) Perpendicular
d) Unrelated
Answer: c
Explanation: When a conductor carries a certain value of current, the force developed in the conductor, the current in the conductor and the magnetic field in the conductor are mutually perpendicular to each other.
10. The relation between the direction of current and the direction of the force is _________
a) Same direction
b) Opposite direction
c) Perpendicular
d) Unrelated
Answer: c
Explanation: When a conductor carries a certain value of current, the force developed in the conductor, the current in the conductor and the magnetic field in the conductor are mutually perpendicular to each other.
Characteristics of Lines of Magnetic Flux
1. Magnetic field lines seek the path of __________ resistance.
a) Maximum
b) Minimum
c) Infinite
d) Zero
Answer: b
Explanation: Magnetic field lines will always seek the path of least resistance. It does not seek the path of zero resistance because, in practical scenarios, zero resistance is not possible.
2. Magnetic field lines form _________ loops from pole to pole.
a) Open
b) Closed
c) Branched
d) Either closed or branched
Answer: b
Explanation: Magnetic field lines form closed loops from pole to pole. There is no discontinuity in the magnetic flux lines.
3. Do magnetic flux lines intersect?
a) Yes
b) No
c) Depends on the situation
d) Cannot be determined
Answer: b
Explanation: Magnetic field lines do not cross each other because if they cross each other it means that there are two different directions of a magnetic field in that region and that is not possible.
4. Inside the magnet, field lines travel from?
a) North to south
b) South to north
c) West to east
d) East to west
Answer: b
Explanation: Magnetic field lines originate at the north pole and terminate at the south pole of the magnet and magnetic field lines form closed loop so inside the magnet, they move from south to north.
5. Lines of magnetic flux which are parallel and in the same direction __________ each other.
a) Attract
b) Repel
c) Intersect
d) Cancel
Answer: b
Explanation: Lines of magnetic flux which are parallel to each other and in the same direction repel each other because they tend to act as like poles and like poles repel each other.
6. More the number of magnetic flux lines _______ is the force of the magnet.
a) Greater
b) Lesser
c) Either greater or lesser
d) Neither greater nor lesser
Answer: a
Explanation: More the number of magnetic flux lines, greater is the force of the magnet. This is because the magnetic flux lines denote the strength of the field of the magnet.
7. Magnetic field is strong when____________
a) magnetic field lines are closer
b) magnetic field lines are farther
c) magnetic field lines are longer
d) magnetic field lines are thicker
Answer: a
Explanation: Magnetic field is strong where magnetic field lines are closer and weak where magnetic field lines are farther.
Magnetic Field Due to an Electric Current
1. The force existing between two infinite parallel conductors is inversely proportional to ________
a) Radius of the conductors
b) Current in one of the conductors
c) The product of the current in the two conductors
d) The distance between the two conductors
Answer: d
Explanation: When current is flowing in two different conductors, the force between the two conductors is directly proportional to the product of the current in the two conductors and inversely proportional to the distance between the two conductors.
2. When the distance of operation between the two conductors increases, what happens to the force between the two conductors?
a) Increases
b) Decreases
c) Remains the same
d) Becomes zero
Answer: b
Explanation: When the distance of separation increases, the force between the two conductors decrease because the force between two conductors is inversely proportional to the distance of separation between them.
3. Magnetic field at a point d distance away from long wire due to electric current i in it is ____________
a) µ0i/2r
b) µ0i/r
c) µ0i/2πr
d) µ0i/πr
Answer: c
Explanation: Magnetic field at distance d from long wire with carrying current i is given by-
B = µ0i/2πr.
4. The force per unit length existing between two infinite parallel conductors is given by ___________
a) µ0i1i2/2πd
b) µ0i1i2/2d
c) µ0i1/2πdi2
d) µ0i1i2/d
Answer: a
Explanation: Force of infinite conductor is given by Bil if B, i, l are mutually perpendicular
F/l = Bi = µ0i1i2/2πd if d is separation of two infinite parallel conductors.
5. If the radius of the current carrying conductor increases, what is the effect on the force?
a) increases
b) decreases
c) remain same
d) become zero
Answer: c
Explanation: Force of the infinite conductor is given by Bil if B, i, l are mutually perpendicular
F/l = Bi = µ0i1i2/2πd if d is separation of two infinite parallel conductors. It doesn’t depend on the radius of conductor so force remains the same.
6. If current of conductor increases, what is the effect on the force?
a) increases
b) decreases
c) remain same
d) become zero
Answer: a
Explanation: Force of infinite conductor is given by Bil if B, i, l are mutually perpendicular
F/l = Bi = µ0i1i2/2πd if d is separation of two infinite parallel conductors. So, as current increases force increases.
7. If length of current carrying conductor increases, what is the effect on the force?
a) increases
b) decreases
c) remain same
d) become zero
Answer: a
Explanation: Force of infinite conductor is given by Bil if B, i, l are mutually perpendicular
F/l = Bi = µ0i1i2/2πd if d is a separation of two infinite parallel conductors. So, as length of conductor increases force increases.
Magnetic Field of a Solenoid
1. The magnetic field strength of a solenoid can be increased by inserting which of the following materials as the core?
a) Copper
b) Silver
c) Iron
d) Aluminium
Answer: c
Explanation: The Magnetic field of a solenoid increases when we insert an iron core because iron is a ferromagnetic material and ferromagnetic materials help in increasing the magnetic property.
2. If a coil is wound around a steel core and electric current is passed through the coil, the steel core acts as a?
a) Electromagnet
b) Permanent magnet
c) Neither electromagnet nor permanent magnet
d) Either electromagnet or permanent magnet
Answer: b
Explanation: When a coil is wound around a steel core, the steel core behaves like a permanent magnet because it is a ferromagnetic material and once it becomes magnetic it does not lose its magnetic property.
3. What is the formula for the magnetic field due to a solenoid?
a) μnI
b) μn2
c) μNI
d) μN2I2
Answer: a
Explanation: The magnetic field due to a solenoid is:
B= μnI, where μ is the permeability, n is the number of turns per unit length and I is the current in the solenoid.
4. What happens to the magnetic field in the solenoid when the number of turns increases?
a) Increases
b) Decreases
c) Remains constant
d) Becomes zero
Answer: a
Explanation: The magnetic field of a solenoid is directly proportional to the number of turns in it. Hence as the number of turns increases, the magnetic field also increases.
5. What happens to the magnetic field in the solenoid when the current increases?
a) Increases
b) Decreases
c) Remains constant
d) Becomes zero
Answer: a
Explanation: The magnetic field of a solenoid is directly proportional to the current in it. Hence as the current increases, the magnetic field also increases.
6. What happens to the magnetic field in the solenoid when the length of the solenoid increases?
a) Increases
b) Decreases
c) Remains constant
d) Becomes zero
Answer: b
Explanation: The magnetic field of a solenoid is inversely proportional to the length. Hence as the length increases, the magnetic field decreases.
7. The current in a solenoid is 30A, the number of turns per unit length is 500 turns per metre. Calculate the magnetic field if the core is air.
a) 18.84T
b) 18.84mT
c) 1.84T
d) 1.84mT
Answer: b
Explanation: The magnetic field in a solenoid is given by:
B=μnI
Substituting the values in the given values in the equation, B=18.84mT.
8. The magnetic field of the solenoid is 18.84mT, the number of turns per unit length is 500 turns per metre. Calculate the current if the core is air.
a) 300A
b) 30A
c) 3A
d) 300mA
Answer: b
Explanation: The magnetic field in a solenoid is given by:
B=μnI
Substituting the values in the given values in the equation, I=30A.
9. The magnetic field of the solenoid is 18.84mT, the current is 30A. Calculate the number of turns per unit length if the core is air.
a) 1500 turns/m
b) 1000 turns/m
c) 500 turns /m
d) 2000 turns/m
Answer: c
Explanation: The magnetic field in a solenoid is given by:
B=μnI
Substituting the values in the given values in the equation n=500 turns/m.
Force on a Current Carrying Conductor
1. What is the expression for force in a current carrying conductor?
a) F=K/r2
b) F=Kq/r2
c) F=Kq1q2/r2
d) F=Kq1q2/r
Answer: c
Explanation: The force in a current carrying conductor is directly proportional to the product of the two charges and inversely proportional to the square of the distance between them. Hence F=Kq1q2/r2, where K is the constant of proportionality.
2. Force in a conductor is__________ to the product of the charges.
a) Directly proportional
b) Inversely proportional
c) Not related
d) Cannot be determined
Answer: a
Explanation: The force in a current carrying conductor is directly proportional to the product of the two charges and inversely proportional to the square of the distance between them.
3. Force in a conductor is __________ to the square of the distance between the charges.
a) Directly proportional
b) Inversely proportional
c) Not related
d) Cannot be determined
Answer: b
Explanation: The force in a current carrying conductor is directly proportional to the product of the two charges and inversely proportional to the square of the distance between them.
4. Calculate the force between two charges having magnitude 3nC and 2nC separated by a distance of 2micro m.
a) 13.5N
b) 13.5kN
c) 1.35N
d) 1.35kN
Answer: b
Explanation: From the expression:
F=Kq1q2/r2, the value of K being 9*109, we get F=13.5kN.
5. If the flow of electric current is parallel to the magnetic field, the force will be?
a) Zero
b) Infinity
c) Maximum
d) Half the original value
Answer: a
Explanation: Force is a cross product. A cross product involves the sine of the angle between them. If two quantities are parallel to each other, the angle between them is zero. Sin(0) is zero, hence force is zero.
6. The ratio of magnetic force to electric force on a charged particle getting undeflected in a field is ______
a) 1
b) 0
c) 2
d) 4
Answer: a
Explanation: When a charged particle is undeflected in a field, the magnitude of the magnetic force and electric force acting on the particle is the same, hence the ratio is 1.
7. Weakest force in nature is __________
a) Electric force
b) Gravitational force
c) Weak force
d) Magnetic force
Answer: a
Explanation: Gravitational force is the weakest force in nature as it does not bind anything strongly with its help.
8. The relation between the direction of force and the direction of magnetic field is __________
a) Same direction
b) Opposite direction
c) Perpendicular
d) Unrelated
Answer: c
Explanation: When a conductor carries a certain value of current, the force developed in the conductor, the current in the conductor and the magnetic field in the conductor are mutually perpendicular to each other.
9. The relation between the direction of current and the direction of the force is ________
a) Same direction
b) Opposite direction
c) Perpendicular
d) Unrelated
Answer: c
Explanation: When a conductor carries a certain value of current, the force developed in the conductor, the current in the conductor and the magnetic field in the conductor are mutually perpendicular to each other.
Force Determination
1. Which among the following, is the correct expression for force in a current carrying conductor if magnetic field is perpendicular to it?
a) F=Bi
b) F=B2il
c) F=Bil
d) F=Bl2
Answer: c
Explanation: The correct expression for force in a current carrying conductor in a magnetic field perpendicular to it is F=Bil, where B is the magnetic field, i is the current in the conductor and l is the length of the conductor.
2. When the current in the current carrying conductor increases, what happens to the force in the conductor which is at right angles to the magnetic field?
a) Increases
b) Decreases
c) Remains the same
d) Becomes zero
Answer: a
Explanation: The force at right angles to the magnetic field of a current carrying conductor increases when the current increases because it is directly proportional to the force.
3. When the length of the conductor in the current carrying conductor increases, what happens to the force in the conductor which is at right angles to the magnetic field?
a) Increases
b) Decreases
c) Remains the same
d) Becomes zero
Answer: a
Explanation: The force at right angles to the magnetic field of a current carrying conductor increases when the length of the conductor increases because it is directly proportional to the force.
4. When the magnetic field intensity in the current carrying conductor increases, what happens to the force in the conductor which is at right angles to the magnetic field?
a) Increases
b) Decreases
c) Remains the same
d) Becomes zero
Answer: a
Explanation: The force at right angles to the magnetic field of a current carrying conductor increases when the magnetic field intensity increases because it is directly proportional to the force.
5. The unit for force in a current carrying conductor is _________
a) Tesla*Ampere*metre
b) Tesla
c) Ampere/metre
d) Ampere*metre
Answer: a
Explanation: F=B*i*l. So,unit of force=unit of B * unit of i * unit of l = Tesla*Ampere*metre.
Capacitance And Capacitors MCQs
6. If net force is zero on a particle in magnetic field what is relation between velocity and magnetic field?
a) v=E*B
b) v=E/B
c) v=B/E
d) v=1/(E*B)
Answer: b
Explanation: Since net force is zero on the particle.
Electric force = Magnetic force
QE = QvB => E=vB or v=E/B.
7. If the intensity of the magnetic field is 100T, the length of the conductor is 10m and the magnitude of force perpendicular to the magnetic field is 10kN,calculate the current in the conductor.
a) 100 A
b) 100 mA
c) 10 A
d) 10 mA
Answer: c
Explanation: The formula for calculating the value of the force which is perpendicular to the magnetic field is:
F=Bil
Substituting the values from the question, we get i = 10A.
8. If the intensity of the magnetic field perpendicular to current carrying conductor is 100T, the length of the conductor is 3m and the current in the conductor is 10A, calculate the magnitude of force perpendicular to the electric field.
a) 300N
b) 30N
c) 30kN
d) 3kN
Answer: d
Explanation: The formula for calculating the value of the force which is perpendicular to the magnetic field is:
F=Bil
Substituting the values from the question, we get F=3kN.
9. Force in current carrying conductor placed in magnetic field is ___________ of il and B.
a) dot product
b) scalar product
c) cross product
d) vector addition
Answer: c
Explanation: Force in a current carrying conductor is given by cross product of il and B.
Electromagnetic Induction
1. An E.M.F. can be induced by _________
a) Change in the magnetic field only
b) Change in the area of cross section only
c) Change in angle between magnetic field and area only
d) Change in the magnetic field, area or angle between them
Answer: d
Explanation: emf=-dϕ/dt. We know ϕ flux is the dot product of magnetic field vector and area vector.
ϕ=BAcos(θ), hence if either of the three, that is, magnetic field, area or angle changes, the emf will change, flux changes due to which emf can be induced.
2. What happens to the current in a coil while accelerating a magnet inside it?
a) Increases
b) Decreases
c) Remains constant
d) Reverses
Answer: a
Explanation: A change in the magnetic field induces an emf. When there is an emf, there has to be current. Hence, when the magnet is moved inside a coil, the current in it increases.
3. What is the consequence of motor effect?
a) Current
b) Voltage
c) Electromagnetic induction
d) EMF
Answer: c
Explanation: Motor effect is when a current carrying conductor in a magnetic field experiences a force, hence its consequence is electromagnetic induction.
4. The total number of magnetic field lines passing through an area is termed as?
a) Voltage
b) EMF
c) Magnetic flux
d) Magnetic flux density
Answer: c
Explanation: Number of magnetic field lines passing through an area is magnetic flux.
5. The formula for induced emf if magnetic field, length and velocity of conductor all are mutually perpendicular is __________
a) emf=B2l
b) emf=Bil
c) emf=Blv
d) emf=B2v
Answer: c
Explanation: The formula for induced emf is emf=Blv, where B is the magnetic field, l is the length of the conductor and v is the velocity with which it is moving in the magnetic field and all three quantities are mutually perpendicular to each other.
6. If a conductor 0.2m long moves with a velocity of 0.3m/s in a magnetic field of 5T, calculate the emf induced if magnetic field, velocity and length of conductor are mutually perpendicular to each other.
a) 0.3V
b) 0.03V
c) 30V
d) 3V
Answer: a
Explanation: The formula for induced emf is: emf=Blv if B,l,v are perpendicular to each other. Substituting the values of B, l and v from the question, we get emf=0.3V.
7. Find the length of a conductor which is moving with a velocity 0.4m/s in a magnetic field of 8T, inducing an emf of 20V if magnetic field, velocity and length of conductor are mutually perpendicular to each other.
a) 50m
b) 5m
c) 6.25m
d) 0.5m
Answer: c
Explanation: The formula for induced emf is: emf=Blv if B, l, v are perpendicular to each other. Substituting the values of B, emf and v from the question, we get l=6.25m.
8. Find the strength of the magnetic field in a conductor 0.5m long moving with a velocity of 10m/s, inducing an emf of 20V if magnetic field, velocity and length of conductor are mutually perpendicular to each other.
a) 1T
b) 2T
c) 3T
d) 4T
Answer: d
Explanation: The formula for induced emf is: emf=Blv if B, l, v are perpendicular to each other. Substituting the values of l, emf and v from the question, we get B=4T.
9. What does emf stand for?
a) Electronic magnetic force
b) Electromotive force
c) Electromagnetic force
d) Electromated force
Answer: b
Explanation: Emf stands for electromotive force. It is the voltage developed by any source of electrical energy.
10. What is emf?
a) Force
b) Voltage
c) Current
d) Flux
Answer: b
Explanation: Electromotive force is not actually a force. It is basically a voltage. It is the voltage developed by any source of electrical energy.
Direction of Induced EMF
1. According to Faraday’s laws of electromagnetic induction, an emf is induced in a conductor whenever?
a) The conductor is perpendicular to the magnetic field
b) Lies in the magnetic field
c) Cuts magnetic lines of flux
d) Moves parallel to the magnetic field
Answer: c
Explanation: An emf is induced, according to Faraday’s laws of electromagnetic induction, whenever the conductor in a magnetic field cuts the magnetic lines of flux.
2. Direction of induced emf is determined by __________
a) Fleming’s left hand rule
b) Fleming’s right hand rule
c) Faraday’s law
d) Right hand thumb rule
Answer: b
Explanation: Fleming’s left hand rule stated that if the index finger points toward magnetic flux, the thumb towards the motion of the conductor, then the middle finger points towards the induced emf.
3. “The direction of an induced e.m.f. is always such that it tends to set up a current opposing the motion or the change of flux responsible for inducing that e.m.f.”, this is the statement for?
a) Fleming’s left hand rule
b) Fleming’s right hand rule
c) Faraday’s law
d) Lenz’s law
Answer: d
Explanation: The above statement is that of Lenz’s law. It is used to determine the direction of the induced emf.
4. According to Fleming’s right hand rule, the thumb points towards?
a) Current
b) E.M.F.
c) Motion of the conductor
d) Magnetic flux
Answer: c
Explanation: Fleming’s left hand rule stated that if the index finger points toward magnetic flux, the thumb towards the motion of the conductor, then the middle finger points towards the induced emf.
5. According to Fleming’s right hand rule, the index finger points towards?
a) Current
b) E.M.F.
c) Motion of the conductor
d) Magnetic flux
Answer: d
Explanation: Fleming’s left hand rule stated that if the index finger points towards magnetic flux, the thumb towards the motion of the conductor, then the middle finger points towards the induced emf.
6. According to Fleming’s right hand rule, the middle finger points towards?
a) Current
b) E.M.F.
c) Motion of the conductor
d) Magnetic flux
Answer: b
Explanation: Fleming’s left hand rule stated that if the index finger points towards magnetic flux, the thumb towards the motion of the conductor, then the middle finger points towards the induced emf.
7. The relation between the direction of induced emf and the direction of motion of the conductor is?
a) Parallel
b) Equal
c) Not related
d) Perpendicular
Answer: d
Explanation: According to Fleming’s right hand rule, the induced emf, the motion of the conductor and the magnetic flux are mutually perpendicular.
8. The relation between the direction of induced emf and the direction of magnetic flux is _______
a) Parallel
b) Equal
c) Not related
d) Perpendicular
Answer: d
Explanation: According to Fleming’s right hand rule, the induced emf, the motion of the conductor and the magnetic flux are mutually perpendicular.
9. The relation between the direction of magnetic flux and the direction of motion of the conductor is _______
a) Parallel
b) Equal
c) Not related
d) Perpendicular
Answer: d
Explanation: According to Fleming’s right hand rule, the induced emf, the motion of the conductor and the magnetic flux are mutually perpendicular.
Magnitude of the Generated or Induced EMF
1. Which, among the following, is the formula for induced emf?
a) e=dϕ /dt
b) e=dt/dϕ
c) e=t*ϕ
d) e=t2ϕ
Answer: a
Explanation: The formula for induced emf is e = dϕ /dt because the induced emf is the flux linkage per unit time.
2. According to _________________ induced emf is equal to rate of change of magnetic flux.
a) Newton’s law
b) Lenz law
c) Faraday’s law
d) Coulomb’s law
Answer: c
Explanation: According to Faraday law of electromagnetic induction, induced emf is equal to rate of change of magnetic flux.
3. The emf induced in a coil having N turns is?
a) e=ϕ/t
b) e=N*ϕ/t
c) e=N*ϕ*t
d) e=N2*ϕ*t
Answer: b
Explanation: The emf induced in a coil having N turns is, e=N*ϕ/t. This is because, the emf in a single coil is the flux linkage per unit time, that is, phi/t. Hence the flux induced in N turns is N*ϕ/t.
4. According to ____________________ induced emf oppose the cause due to which they are produced.
a) Newton’s law
b) Lenz law
c) Faraday’s law
d) Coulomb’s law
Answer: b
Explanation: According to Lenz law, emf is induced in such a way that it opposes the cause due to which it is produced.
5. North pole induces __________
a) Clockwise current
b) Anti-clockwise current
c) Zero current
d) Infinite current
Answer: b
Explanation: A north pole will always induce an anti-clockwise current whereas a south pole will always induce a clockwise current due to electromagnetic theory.
6. What is the principle of the transformer?
a) Gauss law
b) Coulomb’s law
c) Electromagnetic induction
d) Ampere’s law
Answer: c
Explanation: In transformer, flux in secondary coil change due to current in the primary coil and hence current get induced in secondary coil.
7. Voltage induced in secondary coil of transformer is given by__________________
a) NP*VP/NS
b) NS*VP/NP
c) (NP/VP)*NS
d) NP/(VP*NS)
Answer: b
Explanation: In transformer, VP/VS = NP/NS
So, VS = NS*VP/NP.
Updated Electromagnetism MCQs ( Electrical Engineering ) MCQs – Electrical Engineering MCQs