Physics Chapter 13 - Magnetic Effects of Current

The relationship between electricity and magnetism was discovered by Hans Christian Oersted. He showed that an electric current produces a magnetic field.

A compass needle is a small bar magnet. When placed near a wire carrying an electric current, the needle deflects, indicating the presence of a magnetic field around the wire.

The region surrounding a magnet where its magnetic force can be felt. It's a vector quantity having both direction and magnitude.

A compass needle is a small bar magnet that aligns itself with the Earth's magnetic field.

Lines that represent the direction of the magnetic field around a magnet. Iron filings align themselves along these lines when sprinkled near a magnet.

Magnetic field lines are closed loops that always go from the North pole to the South pole outside the magnet and from the South pole to the North pole inside the magnet.

The strength of a magnetic field is determined by how close together the magnetic field lines are. Closer lines indicate a stronger magnetic field.

The magnetic field lines are always closed loops, which means they always form a complete circle.

The strength of a magnetic field is inversely proportional to the distance between the magnetic field lines. Closer lines indicate a stronger field, while lines farther apart indicate a weaker field.

Magnetic field lines never cross each other. If they did, it would mean a compass needle could point in two directions at the same point, which is impossible.

The magnetic field around a straight current-carrying conductor is circular and concentric, meaning it forms circles around the wire. The direction of the field can be determined using the right-hand thumb rule.

When the direction of current flowing through a conductor is reversed, the magnetic field around the conductor also reverses its direction. This demonstrates the interconnectedness of electricity and magnetism.

A convenient way to find the direction of the magnetic field around a current-carrying conductor. Imagine holding the wire in your right hand with your thumb pointing in the direction of the current. Your curled fingers represent the direction of the magnetic field lines.

The magnetic field around a straight conductor is created by the moving charges (electrons) within the conductor. The strength of the magnetic field is directly proportional to the current flowing through the conductor.

The direction of the magnetic field around a straight conductor can be determined using the right-hand thumb rule. If the thumb points in the direction of the current, the curled fingers indicate the direction of the magnetic field lines.

The magnetic field around a straight current-carrying conductor forms concentric circles around the wire. The closer to the wire, the stronger the magnetic field.

A coil of many closely wound turns of insulated copper wire in the shape of a cylinder.

The magnetic field lines inside a solenoid are parallel and straight, indicating a uniform magnetic field.

A magnet created by passing current through a solenoid, often around a magnetic material like soft iron.

A current-carrying conductor placed in a magnetic field experiences a force perpendicular to its length and the magnetic field lines.

A circular loop carrying current creates a magnetic field. Each point on the wire contributes.

The end of a solenoid where the magnetic field lines exit is considered as the north pole.

The end of a solenoid where the magnetic field lines enter is considered as the south pole.

The process of inducing a current in a coil by changing the magnetic field around it. This change can be caused by moving a magnet near the coil, moving the coil through a magnetic field, or changing the current in a nearby coil.

The phenomenon where a change in current in one coil (primary coil) induces a current in a nearby coil (secondary coil).

The current induced in a coil due to a change in magnetic field is at its maximum when the motion of the coil is perpendicular to the magnetic field lines.

A rule that helps determine the direction of the induced current, magnetic field, and motion of a conductor. It uses the thumb, index finger, and middle finger of your right hand.

Changes in magnetic field lines around a coil create an electromotive force (EMF) which drives the flow of induced current.

Using electromagnetic induction to generate electrical energy by moving a conductor in a magnetic field or vice versa.

The direction of the induced current in a circuit opposes the change in magnetic flux producing it.

The number of magnetic field lines passing through a surface.

Alternating current (AC) changes its direction periodically, usually 50 times per second (Hz) in India and 60 Hz in America. It is characterized by its sinusoidal waveform.

Direct current (DC) flows in only one direction. It is constant and does not change its direction over time.

Electric power can be transmitted efficiently over long distances using AC because it allows for the use of transformers to increase voltage, reducing energy loss due to resistance. This makes AC ideal for long-distance power delivery.

In India, household electric circuits are typically supplied with a voltage of 220V and a frequency of 50Hz.

The live wire in a domestic electric circuit carries the high voltage of 220V.

The neutral wire in a domestic electric circuit provides a return path for the current and is at zero potential.

A wire connected to the ground, providing a low-resistance path for current to flow. This prevents excess current from accumulating on the metallic body of appliances, ensuring safety for users.

A box that houses the main switch, fuse, and often an electrical meter. It serves as a central point for controlling and distributing electricity to various appliances.

A situation where the resistance in an electrical circuit becomes extremely low, causing a surge of current flow. This can potentially damage appliances and wiring due to excessive heat generation.

Occurs when the total electrical load exceeds the capacity of the wire or circuit, causing it to overheat. This can lead to circuit failure and potential fire hazards.

A safety device used in electrical circuits to prevent damage caused by excessive current flow. It melts and breaks the circuit when the current exceeds a predetermined limit, protecting against short circuits and overloading.

Connecting appliances in parallel allows each device to operate independently at a constant voltage, allowing for multiple appliances to be used simultaneously in a household circuit.

A safety feature in domestic circuits that ensures each appliance has its own switch for controlling power.

In a typical household circuit, two circuits are present: one high-capacity circuit (15A) for high-power appliances like air conditioners and another low-capacity circuit (5A) for low-power appliances like lights and fans.