Magnetic Effects of Electric Current

Vocabulary flashcards covering the key terms, scientific concepts, safety devices, and rules from the lecture notes on the magnetic effects of electric current.

Hans Christian Oersted

A 19th-century scientist who discovered in 1820 that a compass needle deflects near an electric current-carrying wire, proving that electricity and magnetism are linked phenomena; the unit of magnetic field strength (oersted) is named in his honor.

Magnetic Field

The region surrounding a magnet in which the force of the magnet can be detected, possessing both magnitude and direction.

Magnetic Field Lines

Closed continuous curves representing the path along which a hypothetical free north pole would move; by convention, they emerge from the north pole and merge at the south pole outside the magnet, and run from south to north inside.

Right-Hand Thumb Rule

A rule stating that if a current-carrying straight conductor is held in the right hand with the thumb pointing in the direction of electric current, the wrapped fingers indicate the direction of the magnetic field lines (also known as Maxwell's corkscrew rule).

Solenoid

A coil of many circular turns of insulated copper wire wrapped closely in the shape of a cylinder, which produces a magnetic field pattern similar to that of a bar magnet with a uniform field consisting of parallel straight lines inside.

Electromagnet

A temporary magnet formed by placing a piece of magnetic material, such as soft iron, inside the coil of a current-carrying solenoid.

Fleming's Left-Hand Rule

A rule stating that if the thumb, forefinger, and middle finger of the left hand are stretched mutually perpendicular, with the forefinger pointing in the direction of the magnetic field and the middle finger in the direction of the current, the thumb indicates the direction of motion or force acting on the conductor.

Live Wire

The positive wire in a domestic electric power supply that typically has red insulation cover.

Neutral Wire

The negative wire in a domestic electric power supply that typically has black insulation cover.

Earth Wire

A safety wire with green insulation connected to a metal plate deep in the ground, providing a low-resistance conducting path for leakage current to prevent electric shocks from metallic appliances.

Domestic Electric Supply Standards

Electric power supplied to domestic households in India with an alternating voltage of $220\,\text{V}$ and a frequency of $50\,\text{Hz}$.

Electric Fuse

A vital safety device connected in domestic circuits that melts due to Joule heating when excessive current flows, breaking the circuit to protect against short-circuiting or overloading.

Short-Circuiting

An abrupt increase of electric current in a circuit occurring when the live wire and neutral wire come into direct contact due to faulty appliances or damaged insulation.

Overloading

A condition occurring in an electric circuit when total current exceeds the safe rating, caused by an accidental hike in supply voltage, short-circuiting, or connecting too many appliances to a single socket.

Magnetic Resonance Imaging (MRI)

A medical imaging technique that uses the temporary magnetic fields produced by ion currents travelling along nerve cells in human body organs (notably the heart and brain) to obtain diagnostic images of internal body parts.