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 17 of 59
- A. High resistance in series
- B. Low resistance in series
- C. High resistance in parallel
- D. Low resistance in parallel
Explanation: An ammeter is a device used to measure the current flowing through a circuit. It is connected in series with the circuit.
Correct answer: Low resistance in parallel322. Ammeter lies in _
- A. Series
- B. Parallel
- C. Either a or b
- D. None of these
Explanation: An ammeter is a device used to measure the current flowing through a circuit.
Correct answer: Series- A. wb/m²
- B. N/Am
- C. Tesla
- D. All of these
Explanation: Magnetic flux density is a measure of the strength of a magnetic field.
Correct answer: All of these- A. I only
- B. II only
- C. Both I and II
- D. None of these
Explanation: A toroid is a coil of wire wound in the shape of a donut or ring. It can be considered as a solenoid that has been bent into a…
Correct answer: Both I and II- A. 2/9 B
- B. 9/2 B
- C. 18 B
- D. 8/18
Explanation: The magnetic field inside a solenoid is given by:B = μ₀nIWhere:B is the magnetic field strengthμ₀ is the permeability of free spacen is…
Correct answer: 9/2 B- A. 2L
- B. L
- C. 3L/2
- D. L/2
Explanation: The equivalent inductance of inductors connected in parallel is given by:1/L_eq = 1/L_1 + 1/L_2 + ...In this case, we have two inductors…
Correct answer: L/2- A. Faraday
- B. Oersted
- C. Henry
- D. None of these
Explanation: Hans Christian Oersted, a Danish physicist, discovered the magnetic effect of electric current in 1820.
Correct answer: Oersted- A. Weber
- B. Tesla
- C. Volt
- D. Weber/m
Explanation: Magnetic flux is a measure of the total magnetic field that passes through a given area.
Correct answer: Weber- A. Centre of the scale
- B. Left end of the scale
- C. Right end of the scale
- D. None of these
Explanation: An ohmmeter is a device used to measure the resistance of a circuit. The scale of an ohmmeter is typically calibrated in ohms, with zero…
Correct answer: Left end of the scale- A. [L A⁻³ T⁻²]
- B. [M L⁻² T⁻²]
- C. [M L² T⁻² A⁻¹]
- D. [M T⁻² A⁻¹]
Explanation: The dimension of magnetic field can be determined from the formula for the force on a moving charge in a magnetic field:F = qvBWhere:F is…
Correct answer: [M L⁻² T⁻²]- A. Increase
- B. Decrease
- C. Will be same
- D. None of these
Explanation: The force on a current-carrying conductor in a magnetic field is given by:F = BIL sinθWhere:F is the force on the conductorB is the…
Correct answer: Decrease- A. Length of solenoid
- B. Number of turns
- C. Magnetic field
- D. All of these
Explanation: The magnetic field inside a solenoid is directly proportional to the current flowing through it.
Correct answer: Magnetic field- A. 5π × 10-9 Wb/Am
- B. 8π × 10-10 Wbm/m
- C. 4π × 10-7 Wb/Am
- D. None of these
Explanation: The permeability of free space, denoted by μ₀, is a fundamental physical constant that represents the ability of a vacuum to support the…
Correct answer: 4π × 10-7 Wb/Am334. If the direction of current in two parallel wires is in opposite direction, then the wires will:
- A. Attract
- B. Repel
- C. Both a and b
- D. None of these
Explanation: When the current flows in the opposite direction in two parallel wires, the magnetic fields produced by the wires interact in such a way…
Correct answer: Repel- A. B/2
- B. B/4
- C. 2B
- D. 4B
Explanation: The magnetic field (B) produced by a long, straight current-carrying wire is inversely proportional to the distance (r) from the wire.
Correct answer: 2B336. When a ferromagnetic material is heated to a temperature above its Curie temperature, the material:
- A. Is permanently magnetized
- B. Remains ferromagnetic
- C. Behaves like a diamagnetic material
- D. Behaves like a paramagnetic material
Explanation: Above the Curie temperature, the thermal energy is sufficient to overcome the magnetic alignment within the domains of a ferromagnetic…
Correct answer: Behaves like a paramagnetic material- A. NBA/ω
- B. NBAω
- C. NBA/ω2
- D. NBAω²
Explanation: The induced emf in a rotating coil is given by ε = NBAω sin(ωt). The maximum value of the sine function is 1, so the maximum induced emf…
Correct answer: NBAω- A. 8.4V
- B. 84V
- C. 42V
- D. 4.2V
Explanation: The induced emf is given by Faraday's Law, ε = -N (ΔΦ/Δt). The change in flux (ΔΦ) for a 180° rotation is from BA to -BA, so ΔΦ = 2BA.
Correct answer: 84V- A. 37.7V
- B. 188.5V
- C. 113.1V
- D. 150.8V
Explanation: N=50, B=0.5T, A=0.02 m², ω≈377 rad/s → emf = 50×0.5×0.02×377 ≈ 188.5 V.
Correct answer: 188.5V- A. 5 x 10⁹ C/kg
- B. 2.5 x 10¹¹ C/kg
- C. 5 x 10¹¹ C/kg
- D. 5 x 10¹² C/kg
Explanation: Magnetic force provides the centripetal force for circular orbit, so qvB = mv²/r.
Correct answer: 2.5 x 10¹¹ C/kg