Free Electromagnetic Induction MCQs with Answers
288 Electromagnetic Induction MCQs from Physics, each with the correct answer and a written explanation of why it is correct. Free and unlimited, with no account needed.
Changing magnetic flux induces an emf according to Faraday's law, while Lenz's law gives the direction that opposes the change producing it. Transformers apply induction between coils to step alternating voltage up or down, with turns ratio, current transformation and energy losses determining practical operation.
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Read the Electromagnetic Induction notesFree MDCAT chapter notes with key terms288 questions · page 14 of 15
- A. NmA-2s-1
- B. NmAs-1
- C. NmA-1s-1
- D. NmA-2s1
Explanation: The unit of magnetic flux change (∆Φ) is measured in webers (Wb), and the unit of time change (∆t) is measured in seconds.
Correct answer: NmA-1s-1- A. Rotated about a north-south axis
- B. Rotated about an east-west axis
- C. Moved rapidly, without rotation toward the east
- D. Moved rapidly, without rotation toward the south
Explanation: When the copper hoop is rotated about an east-west axis, the maximum induced emf is produced.
Correct answer: Rotated about an east-west axis- A. Zero
- B. 2
- C. 1
- D. 1/2
Explanation: B is the correct option. This option is correct. The emf will be maximum when the value of the sine function is at its maximum.
Correct answer: 1- A. Coulomb's law
- B. Faraday's Law
- C. Ampere's law
- D. Hook's law
Explanation: Transformers and generators work on the principle of Faraday s Law.
Correct answer: Faraday's Law- A. emf.
- B. Resistance.
- C. Shear
- D. Currents.
Explanation: Lenz's law refers to induced currents and not to induced EMF, which means that we can apply it directly to closed conducting loops or…
Correct answer: Currents.- A. Is reduced
- B. Is increased
- C. Remains same
- D. None of these
Explanation: A transformer essentially converts between voltage and current using a magnetic field, a step down transformer, steps down the input…
Correct answer: Is increased- A. By increasing the turn ratio
- B. By decreasing the turn ratio
- C. By minimizing Eddy currents
- D. By selecting core materials with a large hysteresis area
Explanation: Explanation:This option is correct because the flow of Eddy currents in the core of the transformer results in power loses due to heat.
Correct answer: By minimizing Eddy currents- A. Magnetic, electrically
- B. Electrical, magnetically
- C. Magnetic, magnetically
- D. Electrical, optically
Explanation: In a transformer, there is no electrical connection between the two coils, which are typically referred to as the primary and secondary…
Correct answer: Electrical, magnetically- A. Power input is equal to Power output.
- B. Power input is less than half of the power output.
- C. Power input is greater than Power output
- D. Power input is more than half of the power output.
Explanation: A is Correct, as an ideal transformer operates with 100% efficiency, meaning no energy is lost
Correct answer: Power input is equal to Power output.- A. 65V
- B. 260V
- C. 60V
- D. 10V
Explanation: We know that generated EMF in the DC generator is given by the formula: E = ΦPNZ/60A Where Φ= flux P= No. of poles N= speed Z= No.
Correct answer: 65V- A. Magnetic field
- B. Electric field
- C. Induced emf
- D. Altemating current
Explanation: Protip: Static/ not moving charge: electric field Charge moving with constant velocity: electric and magnetic field
Correct answer: Magnetic field- A. Be maximum
- B. Be zero
- C. Depend on the size of the coil
- D. None of above
Explanation: Since the coil is moving parallel to a uniform magnetic field, the magnetic flux associated with the coil will remain zero during the…
Correct answer: Be zero- A. Area of the coil:
- B. Shape of the coil
- C. Turns of coil:
- D. Strength of magnetic field in which coil rotates
Explanation: According to Faraday's law of electromagnetic induction, the magnitude of the induced electromotive force (emf) and hence the current…
Correct answer: Strength of magnetic field in which coil rotates- A. Current
- B. Resistance
- C. Magnetic induction
- D. Potential difference
Explanation: The time rate of change of magnetic flux has the same dimensions as potential difference, which is measured in volts (V).
Correct answer: Potential difference- A. 0 mA
- B. 2 mA
- C. 2.8 mA
- D. 20 mA
Explanation: The induced current in the loop is 2.8 mA. The rate of loss of kinetic energy is equal to the power dissipated in the loop, which is given…
Correct answer: 2.8 mA- A. resotoring torque
- B. defelection torque
- C. back motor effect
- D. all of these
Explanation: When the current I passes through the coil, the coil experiences torque, which rotates the coil through an angle alpha.
Correct answer: all of these- A. Charge
- B. Current
- C. Energy
- D. Magnetic field
Explanation: Lenz's law exemplifies the law of conservation of energy. It states that the induced electromotive force (emf) in a closed loop will…
Correct answer: Energy- A. Ohm's law
- B. Coulomb's law
- C. Lenz's law
- D. Newton's law of motion
Explanation: Lenz's law of electromagnetic induction states that the direction of the current induced in a conductor by a changing magnetic field is…
Correct answer: Lenz's law- A. Law of conservation of current
- B. Law of conservation magnetization
- C. Law of conservation of charges
- D. Law of conservation of energy
Explanation: Lenz's Law is a fundamental principle in electromagnetism. It states that when there is a change in the magnetic field through a…
Correct answer: Law of conservation of energy- A. Transformer
- B. Generator
- C. Galvanometer
- D. Avometer
Explanation: A transformer is the most common application of mutual induction that uses this phenomenon to change the values of alternating voltages…
Correct answer: Transformer