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 36 of 59
- A. Area surrounded by a magnet
- B. Strength of the magnetic field
- C. Rate of change of magnetic force
- D. The number of magnetic lines of force
Explanation: Magnetic flux is number of magnetic field lines passing through a surface placed perpendicular to it. Hence, option D is correct.
Correct answer: The number of magnetic lines of force- A. Decreasing area of coil
- B. Decreasing magnetic field
- C. Increasing area of coil
- D. Slowing down speed of coil
Explanation: As, ε = BΔA/Δt Thus, induced emf can be increased by increasing area of coil. Hence, option C is correct.
Correct answer: Increasing area of coil- A. 70 Hz
- B. 50 Hz
- C. 100 Hz
- D. 30 Hz
Explanation: Pakistan operates on a 230V supply voltage and 50Hz.
Correct answer: 50 Hz- A. Ampere's Law
- B. Faraday's Law
- C. Lenz's Law
- D. Joule's Law
Explanation: Lenz's law, in electromagnetism, states that an induced electric current flows in a direction such that the current opposes the change…
Correct answer: Lenz's Law- A. Tesla
- B. Weber
- C. Gauss
- D. Henry
Explanation: The unit of magnetic flux is the Weber (Wb).
Correct answer: Weber- A. Lenz's law
- B. Faraday's law
- C. Magnetic induction
- D. Ampere's law
Explanation: Magnetic induction, also known as electromagnetic induction, is the fundamental principle behind the operation of transformers.
Correct answer: Magnetic induction- A. Magnetic field and scalar area
- B. Magnetic field and vector area
- C. Magnetic field per unit scalar area
- D. Magnetic field per unit vector area
Explanation: The physical description of magnetic flux through a surface is the surface integral of the scalar product (dot product) of the magnetic…
Correct answer: Magnetic field and vector area- A. Magnetic flux density
- B. Magnetic flux
- C. Magnetic force
- D. Work done
Explanation: The dimension of magnetic field (B) is the same as that of magnetic flux density (A) because both are measured in the unit Tesla (T) in…
Correct answer: Magnetic flux density- A. Self-induction
- B. Mutual induction
- C. Eddy current
- D. Choke
Explanation: When an emf is produced in a coil because of the change in current in a coupled coil, the effect is called mutual inductance
Correct answer: Mutual induction- A. Direct current
- B. Alternating current
- C. Direct and alternating current
- D. Direct and alternating voltage
Explanation: Transformers only work for alternating current, because you need a changing magnetic field.
Correct answer: Alternating current- A. Faraday law
- B. Max planks law
- C. Ohm law
- D. Lenz law
Explanation: Lenz's law is applicable to the operation of magnetic levitation trains.
Correct answer: Lenz law- A. 0.5 T
- B. 0.5 Wb
- C. 0.25 Wb
- D. 0.25 T
Explanation: The correct statement is B. 0.5 Wb. To calculate the magnetic flux, you need to use the formula: Magnetic Flux (Φ) = Magnetic Field…
Correct answer: 0.5 Wb- A. Parallel to magnetic field
- B. At 45 degree in magnetic field
- C. Perpendicular to magnetic field
- D. Antiparallel in magnetic field
Explanation: The correct statement is C. Perpendicular to the magnetic field. To achieve the maximum magnetic force on a current-carrying conductor in…
Correct answer: Perpendicular to magnetic field- A. Iron core
- B. Copper core
- C. Gold core
- D. Steel core
Explanation: The correct statement is A. Iron core. In principle, transformers consist of two coils of copper wire wound on the same iron core.
Correct answer: Iron core- A. Self-inductance
- B. Back emf
- C. Motional emf
- D. Mutual inductance
Explanation: The correct statement is B. Back emf. Back emf is often used to describe the induced emf in a coil or motor, especially in the context of…
Correct answer: Back emf- A. NωAB Sinθ
- B. NωAB Cosθ
- C. NωAB
- D. ILB Cosθ
Explanation: The correct statement is A. NωAB Sinθ. This expression represents the emf produced by an AC generator when the coil is rotated in a…
Correct answer: NωAB Sinθ- A. Current
- B. Magnetic Induction
- C. Charge
- D. Emf
Explanation: Emf: Correct. According to Faraday's Law, the rate of change of magnetic flux (Δϕ/Δt ) is directly related to the induced emf, which has…
Correct answer: Emf- A. Up
- B. Down
- C. North
- D. South
Explanation: The hydrogen atom, which is effectively a proton in this context since it has lost its electron, is moving east in a magnetic field…
Correct answer: Up- A. 0.5 hr
- B. 1 hr
- C. 1.5 hr
- D. 2 hr
Explanation: The power of the AC is given as 1000 watts, which is equivalent to 1 kilowatt.
Correct answer: 1 hr- A. 0° and 180°
- B. 90° and 180°
- C. 180° and 270°
- D. 270° and 360°
Explanation: The magnitude of magnetic flux (Φ) through a surface is given by the formula Φ = B·A·cos(θ), where B is the magnetic field strength, A is…
Correct answer: 0° and 180°