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 12 of 59
- A. depends on the rate of change of current
- B. is proportional to the square of the inductance
- C. has units J/H
- D. none of the above
Explanation: The energy stored in an inductor is given by the formula \( W = \frac{1}{2}LI^2 \), where:- \( W \) is the stored energy,- \( L \) is the…
Correct answer: depends on the rate of change of current- A. Small output
- B. Eddy currents and magnetic hysteresis
- C. Soft iron core
- D. Back emf
Explanation: Power loss in transformers primarily occurs due to two factors:- Eddy currents: These are circulating currents induced in the conductive…
Correct answer: Eddy currents and magnetic hysteresis- A. the electric current flows through the wire
- B. the acceleration of the magnet is less than gravitational acceleration
- C. the acceleration of the magnet is equal to gravitational acceleration
- D. both A and B
Explanation: When a magnet falls through a copper circular wire, it induces an electromotive force (EMF) in the wire according to Faraday's law of…
Correct answer: the electric current flows through the wire- A. ms^(-1)A.
- B. ms^(-2)A^(-1)
- C. (c) kgm^2s^(-3)A^(-1)
- D. kgms^2A^(-1)
Explanation: The correct unit for induced electromotive force (emf) is volts (V), and 1 volt is equivalent to 1 joule per coulomb.
Correct answer: ms^(-1)A.- A. Heated
- B. Placed in a time-varying magnetic field
- C. Placed in an electric field
- D. Placed in a uniform magnetic field
Explanation: Eddy currents are circulating currents induced in a conductor when it is exposed to a changing magnetic field.
Correct answer: Placed in a time-varying magnetic field- A. Perpendicular to each other
- B. Parallel to each other
- C. 45 degrees to each other
- D. Can have any angle between them
Explanation: In an electromagnetic wave, the electric field vector E and the magnetic field vector B are perpendicular to each other and also…
Correct answer: Perpendicular to each other- A. primary are less
- B. primary are more
- C. primary and secondary are equal
- D. primary are infinite
Explanation: In a step-up transformer, the primary coil has fewer turns than the secondary coil.
Correct answer: primary are more- A. Galvanometer
- B. Ammeter
- C. Voltmeter
- D. Transformer
Explanation: An electric motor converts electrical energy into mechanical energy, and devices like galvanometer and ammeter are not typically designed…
Correct answer: Voltmeter- A. 1/3
- B. 3
- C. 1
- D. 6
Explanation: The turns ratio (\(N\)) of a transformer is the ratio of the number of turns in the secondary coil (\(N_s\)) to the number of turns in the…
Correct answer: 3- A. Step down
- B. Input voltage and output voltage remain the same
- C. Step up
- D. Amplifier is used
Explanation: For long-distance transmission of electrical power, it is more efficient to use high voltage (low current) to minimize power losses in the…
Correct answer: Step up- A. Induced current
- B. Eddy current
- C. Back emf
- D. None of the above
Explanation: The phenomenon described in the question is related to electromagnetic induction.
Correct answer: Induced current- A. Lenz's law
- B. Faraday's law
- C. Mutual induction
- D. Law of conservation of power
Explanation: A transformer operates based on the principle of mutual induction. Mutual induction is the process where a changing current in one coil…
Correct answer: Mutual induction- A. Maximum
- B. Zero
- C. Intermediate values
- D. None of the above
Explanation: When an electric motor is operating at its maximum speed, the back electromotive force (EMF), often referred to as back emf or counter…
Correct answer: Maximum- A. πB(r2-r2)/Δt
- B. πB(r2-r2)2/Δt
- C. B(r2-r2)/Δt
- D. B(r2+r2)/Δt
Explanation: The induced electromotive force (EMF) in a coil with a changing area in a magnetic field is given by Faraday's law as EMF =- Δ/Δt.where Δ…
Correct answer: πB(r2-r2)/Δt- A. Magnetic flux density
- B. Torque
- C. Mutual induction
- D. Motional emf
Explanation: According to Faraday's law of electromagnetic induction, the induced electromotive force (emf) in a conductor moving perpendicular to a…
Correct answer: Magnetic flux density- A. μοηλεΑ
- B. μοη24/∈
- C. μοΝ2Α/∈
- D. Β. Α.Ε. Ν
Explanation: The self-inductance (L) of a long solenoid is given by the formula: L = HOn2A/lwhere:µo is the permeability of free space,n is the number…
Correct answer: μοηλεΑ- A. 20V
- B. 60V
- C. 45V
- D. 15V
Explanation: The transformation ratio of a transformer is given by the ratio of the number of turns in the secondary coil to the number of turns in the…
Correct answer: 60V238. Three pure inductors each of 2 H are connected as shown in the fig inductance of the circuit is
- A. 6 H
- B. 2 H
- C. 8/6 H
- D. 3/4 H
Explanation: Leg . = L1 + LLeg = 4 +l1/ Lne+ =1/Leg +1/L31/ Lne+ =1/4H +1/2HLne+ = 4H.2H/ 4H+2H =8H/6
Correct answer: 8/6 H- A. amp/radian
- B. N-m/sec²
- C. N-amp/radian
- D. None of these
Explanation: Option D is the correct answer because none of the other options accurately represent the SI unit of the galvanometer constant, which is…
Correct answer: None of these- A. turn to its right
- B. turn to its left
- C. keep moving in the same direction but its speed will increase
- D. keep moving in the same direction but its speed will decrease
Explanation: C is correct. While an electric field alone wouldn't directly change the speed of a charged particle (electron), in this case, the…
Correct answer: keep moving in the same direction but its speed will increase