Chapter-7|Alternating Current | NCERT 12th Physics: Alternating Current: If the direction of current changes alternatively and its magnitude changes continuously with respect to time is called alternating current. Alternating current changes continuously between zero and maximum value and flows in one direction in the first half cycle and in the opposite direction in the next […]

Chapter-6|Electromagnetic Induction (EMI)| NCERT 12th Physics: AC Generator:  AC generator is a kind of device that produces electrical energy from mechanical work. Principle: An AC generator is based on the phenomenon of electromagnetic induction, which is state that whenever magnetic flux linked with a conductor or coil changes an EMF is induced in the coil.

Chapter-6|Electromagnetic Induction (EMI)| NCERT 12th Physics: Mutual Inductance: The phenomenon according to which an opposing EMF is produced in a primary coil as a result of change in current or magnetic flux linked with a neighbouring coil is called mutual induction. If I₁ is changing, then B in primary coil also changes, B in secondary

Chapter-6|Electromagnetic Induction (EMI)| NCERT 12th Physics: Self Inductance: When a current flows through a coil, it produces magnetic field around it. When current changes, the magnetic field which is linked with the coil get changes, then flux will be change. Any change in flux will produces EMF. This phenomena of getting EMF is called self

Chapter-6|Electromagnetic Induction (EMI)| NCERT 12th Physics: Inductance: Flux linkage of a closely wound coil is directly proportional to the current I i.e.                ΦB∝I For a closely wound coil of N turns, the same magnetic flux is linked with all turns. The flux ΦB with the coil changes, each turn contributes

Chapter-6|Electromagnetic Induction (EMI)| NCERT 12th Physics: Eddy Currents: The current induced in bulk pieces of conductors (metallic plate), when the magnetic flux linked with the conductor, changes are known as eddy currents. Eddy Currents are always produced in a plane perpendicular to the direction of magnetic field. Eddy current shows both heating and magnetic effect.

Chapter-6|Electromagnetic Induction (EMI)| NCERT 12th Physics: Energy Consideration: A Quantitative Study Let r be the resistance of a movable arm PQ of the irregular conductor. We assume that the remaining arms QR, RS and SP have negligible resistances compare to r. Due to the presence of the magnetic field, there is a force on arm

Chapter-6|Electromagnetic Induction (EMI)| NCERT 12th Physics: Motional Electromotive Force and Faraday’s Law: Let a uniform magnetic field B is confined to the region ABCD and a coil PQRS is placed inside the magnetic field. At any instant t, the part P´Q= S´R=y of the coil is inside the magnetic field. Let l be the length

Chapter-6|Electromagnetic Induction (EMI)| NCERT 12th Physics: Lenz’s Law: According to Lenz’s law, the polarity of induced EMF is such that, it tends to produce a current which opposes the change is magnetic flux that produced it. Or The direction of induced EMF or current is always such that, it opposes the cause of it’s generation