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 13 of 15
- A. An ideal transformer
- B. A step-up transformer
- C. A step-down transformer
- D. An automatic transformer
Explanation: A step-down transformer is specifically designed to reduce voltage from a higher input (primary) to a lower output (secondary).
Correct answer: A step-down transformer- A. made up of iron metal.
- B. insulated from each other.
- C. separated with metallic laminations.
- D. separated with laminations having winding wires.
Explanation: Eddy currents are induced in the core of a transformer when there is a changing magnetic flux.
Correct answer: insulated from each other.- A. II only
- B. III only
- C. I and II
- D. I and III
Explanation: The correct answer is Option A: II only. In a transformer, the output voltage is typically greater than the input voltage due to the…
Correct answer: II only- A. I and II.
- B. I and IV.
- C. II and III.
- D. III or IV.
Explanation: A transformer is an electrical device used to transfer electrical energy between two or more circuits through electromagnetic induction.
Correct answer: III or IV.- A. Be zero.
- B. Increase.
- C. Decrease.
- D. Be undetermined.
Explanation: In a transformer, the induced electromotive force (e.m.f.) in the secondary coil is generated by the changing magnetic field created by…
Correct answer: Be zero.- A. Force
- B. Magnetic field
- C. Induced current
- D. Electric field
Explanation: Fleming's right-hand rule gives which direction the current flows. The right hand is held with the thumb, index finger and middle finger…
Correct answer: Force- A. Force
- B. Induced current
- C. Magnetic field
- D. Motion
Explanation: Lenz's law states that the direction of the induced current in a circuit is such that it opposes the change in magnetic flux, which is a…
Correct answer: Induced current- A. Mechanical energy into electrical energy
- B. Chemical energy into mechanical energy
- C. Sound energy into mechanical energy
- D. Electrical energy into mechanical energy
Explanation: A current generator, generates current by converting mechanical energy into electrical energy.
Correct answer: Mechanical energy into electrical energy- A. Inertia
- B. Force
- C. Energy
- D. Momentum
Explanation: Just like inertia tends to maintain its original state of motion or rest.
Correct answer: Inertia- A. Mass
- B. Energy
- C. Charge
- D. Momentum
Explanation: Lenz's law is based on the law of conservation of energy. From the definition of Lenz's law, we know that the induced current is always…
Correct answer: Energy- A. Charge
- B. Mass
- C. Energy
- D. Pressure
Explanation: Lenz's law is also a statement of the law of conservation of energy. It articulates that the direction of the induced electromotive force…
Correct answer: Energy- A. Soft iron
- B. Copper
- C. Nickel
- D. Aluminium
Explanation: The core of a transformer is made of soft iron because it has high permeability so ,it provides complete linkage of magnetic flux of the…
Correct answer: Soft iron- A. To reduce eddy currents
- B. To improve the flux linkage between the primary and secondary coils
- C. To dissipate the heat generated by the two coils
- D. To eliminate the back e.m.f produced in the secondary coils
Explanation: The primary coil and the secondary coil are wound on the soft iron core.
Correct answer: To improve the flux linkage between the primary and secondary coils- A. AC generator
- B. Motor
- C. Transformer
- D. DC generator
Explanation: A transformer is a device which increases or decreases alternating voltage through mutual induction.
Correct answer: Transformer- A. Half wave rectification
- B. Self-induction
- C. Mutual induction
- D. Full wave rectification
Explanation: The transformer works on the principle of Faraday's law of electromagnetic induction and mutual induction.
Correct answer: Mutual induction- A. 150
- B. 160
- C. 170
- D. 200
Explanation: As given,Vp = 200V, Vs = 50V, Ns = 40According to the transformer equation, Np/Ns = Vp/Vs Or, Np = Ns.Vp/VsPutting values, Np = (40 x 200)…
Correct answer: 160- A. Equal to (=)
- B. Less than (<)
- C. Greater than(>)
- D. Not equal
Explanation: In a step-down voltage, we decrease the voltage from the primary to the secondary voltage.
Correct answer: Less than (<)- A. First increases and then becomes zero
- B. First increases and then becomes constant at some value
- C. Increases with the passage of time
- D. Remains zero
Explanation: Explanation:At that instant when the switch is closed momentarily current flows through the secondary coil due to change in magnetic flux.
Correct answer: First increases and then becomes zero- A. 2.5V
- B. 25V
- C. 250V
- D. 0.25V
Explanation: According to faraday's law of electromagnetic induction, whenever there is change in magnetic flux, in this particular case there's change…
Correct answer: 25V- A. 10 V
- B. 12 V
- C. 14 V
- D. 16 V
Explanation: Given: Magnetic field strength = B = 0.6 T Length = L = 1m Velocity = v = 20 m/s emf = ε = ?
Correct answer: 12 V