SSC Stenographer 2026 PYQ — Question 17

Solution: The correct answer is Faraday's Law of Electromagnetic Induction.
Explanation:
☛ Faraday's Law of Electromagnetic Induction states that an electromotive force (EMF) is induced in a circuit whenever there is a change in the magnetic flux linked with it.
☛ This phenomenon was discovered by Michael Faraday in 1831.
☛ In transformers, alternating current passing through the primary winding produces a changing magnetic flux, which induces a voltage in the secondary winding via mutual induction.
☛ In electric generators, mechanical energy rotates a conductor inside a magnetic field to continuously change magnetic flux, thereby generating electricity.
☛ Inductive charging systems also use high-frequency electromagnetic induction to transfer power wirelessly between a transmitter coil and a receiver coil.
Extra Exam-Relevant Facts:
☛ Lenz's Law: Determines the direction of the induced current, stating that it always opposes the change in magnetic flux that produces it; it is based on the law of conservation of energy.
☛ Ohm's Law: States that the electric current flowing through a conductor is directly proportional to the potential difference across its ends (), provided temperature remains constant.
☛ Joule's Law of Heating: States that the heat generated in a conductor is directly proportional to the square of the current, resistance, and time ().
☛ Newton's Third Law of Motion: States that to every action, there is always an equal and opposite reaction.
Important One-Liners for Upcoming Exams:
☛ Who discovered the phenomenon of electromagnetic induction in 1831? → Michael Faraday
☛ Which law determines the direction of an induced electromotive force (EMF)? → Lenz's Law
☛ What is the SI unit of magnetic flux? → Weber (Wb)
☛ What is the SI unit of electrical inductance? → Henry (H)
☛ Which rule is used to find the direction of induced current in a generator? → Fleming's Right-Hand Rule