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 5 of 59
- A. 75 x 10^7 T
- B. 60 x 10+3 T
- C. 4π x 10-3
- D. 750π x 10+3
Explanation: The magnetic field inside a solenoid is given by the formula:B=μ0nIwhere:B = Magnetic field (T)μ0 = Permeability of free space (4π×10−7n =…
Correct answer: 4π x 10-3- A. Its length
- B. Its length and current in it
- C. Its length and number of turns in it
- D. The number of turns and current in it
Explanation: The correct answer is The number of turns and current in it. The magnetic field strength inside a solenoid is determined by the product of…
Correct answer: The number of turns and current in it- A. Normal to the solenoid
- B. The axis of the solenoid
- C. Can't be taken
- D. None of the above
Explanation: Option A: The magnetic field inside a solenoid is parallel to the axis of the solenoid, so the magnetic field is not normal to the…
Correct answer: The axis of the solenoid- A. varying with radial distance
- B. uniform
- C. zero
- D. not enough information
Explanation: A long straight coil of wire can be used to generate a nearly uniform magnetic field similar to that of a bar magnet.
Correct answer: zero- A. Minimum
- B. Maximum
- C. None of these
- D. Zero
Explanation: Inside a solenoid, the magnetic field lines are parallel and very close to each other.
Correct answer: Maximum- A. 4π x 10⁻⁷Wb/Am
- B. 4π x 10⁷Wb/Am
- C. 10⁻⁷Wb/Am
- D. 4πx 10⁻⁶Wb/Am
Explanation: The permeability of free space, μ0, is a physical constant used often in electromagnetism.
Correct answer: 4π x 10⁻⁷Wb/Am- A. Resistor
- B. Capacitor
- C. Inductor
- D. Toroid
Explanation: This is a fact to be memorized. A solenoid bent into a circle is called a toroid. Hence, Option D is correct.
Correct answer: Toroid- A. Magnetic flux density will be halved
- B. Magnetic flux density increases by different amount at different points
- C. Magnetic flux density remains unchanged
- D. Magnetic flux density will be doubled
Explanation: When the number of turns N is doubled but the solenoid length L also doubles, the magnetic flux density B=μ0(NI/L) remains the same.
Correct answer: Magnetic flux density remains unchanged- A. Zero
- B. Small but not zero
- C. Infinite
- D. Larger than 1
Explanation: The magnetic field vector makes a 90˚ angle with the area vector since area vector is always perpendicular to the surface we choose.
Correct answer: Zero- A. Area of cross-section
- B. Number of turns
- C. Magnetic field
- D. None of these options is correct
Explanation: The magnetic flux linked with a coil is directly proportional to the number of turns in the coil.
Correct answer: None of these options is correct- A. 1.5 mWb
- B. 0.15 mWb
- C. 0.015 mWb
- D. 15 mWb
Explanation: The magnetic flux through a surface is given by the formula: Φ = B A cosθ where: Φ = magnetic flux through the surface B = magnitude of…
Correct answer: 0.15 mWb- A. Area
- B. Vector area
- C. Unit area
- D. None of these
Explanation: Magnetic flux is the amount of magnetic field passing through a given area.
Correct answer: Vector area- A. Scalar
- B. Vector
- C. Simple
- D. None of these
Explanation: As we are using dot products, the magnetic flux is a scalar quantity. Note: When the magnetic field is along the area of the closed…
Correct answer: Scalar- A. BA cos(θ)
- B. BA
- C. B
- D. BA sin(θ)
Explanation: In physics, specifically electromagnetism, the magnetic flux through a surface is the surface integral of the normal component of the…
Correct answer: BA cos(θ)- A. B and V
- B. B and A
- C. B and I
- D. none of these
Explanation: Option B is correct since magnetic flux is the scalar product (dot product) of the magnetic field vector and area vector.
Correct answer: B and A- A. -20 wb
- B. 30 wb
- C. 20 wb
- D. 80 wb
Explanation: The maximum flux through a loop of area A placed in a magnetic field B is given by the product of the area and the component of the…
Correct answer: 20 wb- A. Zero
- B. Small but not zero
- C. Infinite
- D. Large but not infinite
Explanation: Option A is correct since if the surface is parallel to the field, then no field lines will cross that surface, and the flux through that…
Correct answer: Zero- A. 10 Wb
- B. 15 Wb
- C. 20 Wb
- D. 0 Wb
Explanation: Given:Magnetic field vector, B = i + 5j + 2kArea vector, A = 6i - 2j + 2kThe magnetic flux (Φ) is given by the dot product of the magnetic…
Correct answer: 0 Wb- A. B and V
- B. B and A
- C. B and I
- D. None of these options are correct
Explanation: Magnetic Flux Φ is the dot / scalar product of magnetic flux density B, and cross-sectional area of coil A. Therefore, Φ = B.A.
Correct answer: B and A- A. Minimum
- B. Maximum
- C. Zero
- D. Negative
Explanation: The work done on a charged particle moving in a uniform magnetic field is zero.
Correct answer: Zero