Free Electromagnetism MCQs with Answers
1,176 Electromagnetism MCQs from Physics, each with the correct answer and a written explanation of why it is correct. Free and unlimited, with no account needed.
Magnetic flux density and magnetic flux describe the strength of a magnetic field and the field passing through a surface. A charged particle moving through a magnetic field experiences a force perpendicular to its velocity and may follow circular or helical motion, depending on the angle between velocity and field.
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Read the Electromagnetism notesFree MDCAT chapter notes with key terms1,176 questions · page 50 of 59
- A. Time
- B. Voltage
- C. Current
- D. Displacement
Explanation: Mathematically, the value of AC voltage at time t is given by the equation V=Vosin(ωt)
Correct answer: Time- A. Flux
- B. Density
- C. Flux density
- D. Tesla
Explanation: The magnetic induction B is the flux per unit area of a surface perpendicular to B, hence it is also called as flux density.
Correct answer: Flux density- A. Emf will not be induced
- B. Emf will be induced
- C. Sometimes emf will be induced and sometimes not
- D. Nothing can be predicted
Explanation: As the copper wire cuts the magnetic lines of force, the free charges in the wire will experience a force and will get displaced.
Correct answer: Emf will be induced- A. Clockwise, Zero
- B. Anticlockwise, zero
- C. Anticlockwise, clockwise
- D. Zero, zero
Explanation: Option A is correct as A magnet falls with the S-pole along the axis of the ring.
Correct answer: Clockwise, Zero- A. The self-induced current opposes its cause
- B. The accordance of equation with the Lenz's Law
- C. The induced e.m.f opposes the change which produces it.
- D. All of the above
Explanation: All options are correct by using Lenz's law
Correct answer: All of the above- A. Resistance of the coil
- B. Pole strength of the pole
- C. Motion of the magnet
- D. Number of turns of the coil
Explanation: The explanation is given below:Option A Is correct according to the equation given below as induced emf only depends on the rate of change…
Correct answer: Resistance of the coil- A. 1 revolution
- B. 2 revolution
- C. 1/4 revolution
- D. 1/2 revolution
Explanation: For 1st half rotation induced EMF in a wire loop present in a magnetic field is given as a sinusoidal function.
Correct answer: 1/2 revolution- A. Must dcrease
- B. Must increase
- C. Must remain constant
- D. Can either increase or decrease
Explanation: Induced emf can only be produced when magnetic flux changes as stated in faradays law
Correct answer: Can either increase or decrease- A. E increases
- B. Q remains same
- C. I increase
- D. Q increase
Explanation: The induced charge doesn't depend upon the speed of the magnet. With the increasing in the time rate of change flux, both induced emf and…
Correct answer: Q increase- A. Zero
- B. Counter clockwise
- C. Clockwise
- D. In a direction that depends on the ratio of the loop radii
Explanation: Current will be induced in inner loop in a counter-clockwise direction.
Correct answer: Counter clockwise- A. BNA
- B. Baω/N
- C. BNAω
- D. Zero
Explanation: As ε=NωABsin0 For maximum induced ε=NωAB
Correct answer: BNAω- A. Current
- B. Power
- C. Voltage
- D. Frequency
Explanation: A step-down transformer, the current is increased on the secondary side compared to the primary side.
Correct answer: Current- A. Current
- B. Power
- C. Potential
- D. Frequency
Explanation: From relation current and voltage changes. Only for ideal transformer power remain same otherwise power also changes (decreases due to…
Correct answer: Frequency- A. Convert alternating current to direct current
- B. Convert direct current to alternating current
- C. Convert mechanical energy to electrical energy
- D. Change the level of alternating voltage
Explanation: Option D is corect because transformer only works with alternating voltage and it is used increase or decrease the alternating voltages.
Correct answer: Change the level of alternating voltage- A. Remain same
- B. Decrease because voltage increase
- C. Increases because current decreases
- D. May increases if voltage remain same
Explanation: In an ideal transformer power remain same. VpIp=VsIs
Correct answer: Remain same- A. Primary coil
- B. Iron core
- C. Secondary coil
- D. All of these
Explanation: The magnetic flux changes through solid conductor (core material), induce current (i.e eddy current) are setup in closed path in the body…
Correct answer: Iron core997. _is the energy expended to magnetize and demagnetize the core material in each cycle of the A.C..
- A. Power loss
- B. Hysteresis loss
- C. Heat loss
- D. All of the above
Explanation: Some of the energy is wasted in magnetization and demagnetization of core due to a.c. This is called hydsteresis loss.
Correct answer: Hysteresis loss- A. Eddy current losses
- B. iron losses
- C. Hysterisis losses
- D. Heal loses due to resitance
Explanation: The insulation between lamination sheets should be perfect so as to stop the flow of eddy currents.
Correct answer: Eddy current losses- A. Eddy current
- B. Resistance of the coil
- C. Magnetic hysteresis
- D. All
Explanation: (i)The eddy current results in power dissipation and heating of the core material.
Correct answer: All- A. 360W
- B. 300W
- C. 460W
- D. Zero
Explanation: For ideal transformer Po=P1 Ip=3A Vp=120V P=(Ip)(Vp)=120 X 3 = 360W
Correct answer: 360W