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.
Last updated
Read the Electromagnetism notesFree MDCAT chapter notes with key terms1,176 questions · page 26 of 59
- A. 2✓2eB
- B. 4eB
- C. 2eB
- D. eB
Explanation: Let's calculate the force:F = (2e) * (2 m/s) * B * sin(45°)Since sin(45°) = √2 / 2, we have:F = (2 * 1.602 x 10^-19 C) * (2 m/s) * B * (√2…
Correct answer: 2✓2eB502. If the supply frequency of a transformer increases, the secondary output voltage of the transformer:
- A. Increases
- B. Decreases
- C. Remains unchanged
- D. All of the above
Explanation: If the supply frequency of a transformer increases, the secondary output voltage of the transformer increase.
Correct answer: Increases503. Magnetic flux is maximum when the angle, between the area vector and the magnetic field lines, is?
- A. 0°
- B. 90°
- C. 120°
- D. All of these
Explanation: Magnetic Flux refers to the number of magnetic field lines, passing through a particular area.
Correct answer: 0°- A. Helical
- B. Elliptical
- C. Hyperbolic
- D. Circular
Explanation: The correct answer is that the magnetic field lines around a straight current-carrying wire are circular.
Correct answer: Circular505. A metal rod of length 4 m, velocity 5 m/s and magnetic field 0.5 T will have an induced EMF of:
- A. 10 V
- B. 20 V
- C. 30 V
- D. 4 V
Explanation: Induced EMF = E = B v l where E is the induced EMF, B is the magnetic flux density, v is the speed and l is the length of the rod.
Correct answer: 10 V- A. Directly proportional
- B. Inversely proportional
- C. Directly squared proportional
- D. Not enough information is available
Explanation: Voltage in the secondary coil is inversely proportional to the current in the secondary coil when the resistance is constant.
Correct answer: Inversely proportional- A. 314 Wb
- B. 107 Wb
- C. 157 Wb
- D. 435 Wb
Explanation: Magnetic flux formula: flux = BA cosθB = Magnetic Field A = areaThe angle is the angle between a perpendicular vector to the area and the…
Correct answer: 157 Wb- A. 3.84 x 10^-15 N
- B. 0
- C. 3.84 x 10^-12 N
- D. 38.4 x 10^-15 N
Explanation: Neutrons do not experience magnetic fields because it's a neutral particle, moving charged particles only experience the magnetic force
Correct answer: 0- A. 2.0 x 10^-3 V
- B. 0.50 x 10^-2 V
- C. 1.0 x 10^-2 V
- D. 1.0 x 10^-3 V
Explanation: Motional emf = Bℓv (B,ℓ, and v perpendicular)Emf = (0.20T) * (0.1m) * (0.5m/s) = 0.01 = 1 * 10-2 V
Correct answer: 1.0 x 10^-2 V510. Magnetic flux is a?
- A. Scalar quantity
- B. Vector quantity
- C. Sometimes scalar sometimes vector
- D. None of these
Explanation: Magnetic flux ΦB = BAcosOr it is a dot product, so we may say thatΦB = B.AWhere B = vector for magnetic field, and A = vector for area.The…
Correct answer: Scalar quantity- A. Changes direction
- B. Changes strength
- C. Changes polarity
- D. Does not change
Explanation: Magnetic flux is defined as the number of magnetic field lines passing through a given surface area.
Correct answer: Does not change- A. 0 degree
- B. 90 degree
- C. 45 degree
- D. 60 degree
Explanation: According to the formula,ΦB = BAcosθWe know that cosθ gives its maximum value (1) when θ = 0°.ΦB = BAcos0°ΦB = BA(+1)ΦB = BAHence, option…
Correct answer: 0 degree- A. Oersted
- B. Maxwell
- C. Einstein
- D. Fleming
Explanation: The right-hand thumb rule was invented by British physicist John Ambrose Fleming in the late 19th century for use in electromagnetism.
Correct answer: Fleming- A. Electron
- B. Proton
- C. Neutron
- D. Any charged particle
Explanation: The Lorentz force equation, F = e(v x B), is applicable to any charged particle because it describes the force experienced by a charged…
Correct answer: Any charged particle- A. 1 V
- B. 500 V
- C. 19 V
- D. 43 V
Explanation: Induced emf = NBA ω= 30 x 0.15 x 0.05 x 84 = 18.9 V
Correct answer: 19 V- A. Ohm
- B. Ampere
- C. Volt
- D. Newton
Explanation: This is a standard answer. The SI unit of EMF is Volts. Volts is also the SI unit of Potential difference. 1 Volt = Joule/Coulomb
Correct answer: Volt- A. Non intersecting
- B. Intersect near south pole
- C. Intersect near north pole
- D. Intersect everywhere
Explanation: The magnetic field lines do not intersect, under normal conditions, without any external influences.
Correct answer: Non intersecting- A. Out of page
- B. Move downward
- C. Move randomly
- D. Moves in straight line
Explanation: Cathode rays (which are streams of electrons) are deflected perpendicular to both the magnetic field and their direction of motion when…
Correct answer: Out of page519. In order to enhance magnetic flux, the primary and secondary coils of the transformer are wound on:
- A. Soft iron core
- B. Iron core
- C. Hard iron core
- D. Steel core
Explanation: The correct option is A. In transformers, the core is made of soft iron due to its high magnetic permeability, which enhances magnetic…
Correct answer: Soft iron core- A. The electric field must not be zero.
- B. The magnetic field must not be zero.
- C. The electric field must be zero.
- D. The magnetic field alone can exert a force on the particle.
- E. Option A and D are correct.
Explanation: The correct answers are A) and D).Electromagnetic force on a charged particle is due to both electric and magnetic fields.
Correct answer: The electric field must not be zero.