Physics · Electromagnetic Induction · NEET
No. Resistance opposes the current itself (it wastes energy as heat, V = IR). Inductance opposes only a CHANGE in current (dI/dt), and it stores energy in a magnetic field instead of wasting it. A steady, unchanging current feels no opposition from an ideal inductor at all — its opposing emf appears only while the current is rising or falling.
L tells you how much magnetic flux linkage a coil creates per unit of current. From NΦ = L·I, we get L = NΦ / I. A big L means the coil packs a lot of flux linkage for each ampere, so it fights current changes strongly. It is a fixed geometric property of the coil, not a reading that changes with current.
It is named after Joseph Henry. One henry is the inductance of a coil in which a current changing at 1 ampere per second induces an emf of 1 volt (from emf = L·dI/dt, 1 H = 1 V·s/A). Equivalently, 1 H = 1 weber per ampere, because L = NΦ/I links flux (weber) to current (ampere).
No (for a coil with a non-magnetic core). L depends only on the geometry — number of turns, area, length — and the core material (through μ). If you double the current, both the flux Φ and I double, so their ratio L = NΦ/I stays the same. This is a common trap: students think more current means more inductance. It does not.
Self-inductance is a coil opposing a change in its OWN current (flux it creates through itself). Mutual inductance is when a changing current in one coil induces an emf in a SECOND nearby coil. Both are 'inductance' and both are measured in henry; the next step is to study self-inductance in detail.
A long solenoid has 1000 turns. When a current of 4 A flows through it, the magnetic flux linked with each turn of the solenoid is 4 × 10⁻³ Wb. The self-inductance of the solenoid is:
The magnetic energy stored in an inductor of inductance 4 µH carrying a current of 2 A is:
Try the real previous-year questions from this chapter — each with the answer and a full solution.
Inductance is the property of a coil (measured in henry) that opposes any change in the current through it by storing energy in a magnetic field.
The henry (symbol H). 1 H = 1 volt-second per ampere = 1 weber per ampere.
L = NΦ / I, where N is the number of turns, Φ is the flux per turn, and I is the current. Equivalently, from emf = L·(dI/dt).
No. For a non-magnetic core it depends only on the coil geometry (turns, area, length) and the core material. Flux changes with current, but L stays constant.
It underlies self-inductance, mutual inductance, energy stored (½LI²) and AC circuits — high-frequency PYQ topics. Getting the definition L = NΦ/I clear makes every later numerical fast.
