Electric Current and Charge in Motion

What is the primary phenomenon described in Chapter 1?

What is the net amount of charge flowing across an area in a given time interval?

What is the physical quantity represented by the symbol I?

What is the characteristic of the flow of charges in lightning?

What is the analogy used to describe the flow of charges in devices?

What is the implication of a negative number in the context of electric current?

What is the unit of current in SI units?

What is the typical order of magnitude of currents in domestic appliances?

What is the main reason why electrons are not free to move in atoms and molecules?

What happens to electrons when an electric field is applied to a conductor?

Electric Current

Electric currents occur naturally, such as in lightning, and are also present in everyday devices, like torches and cell-driven clocks.
In a steady electric current, charges flow in a smooth and continuous manner.

Defining Electric Current

The net amount of charge flowing across a small area in a given time interval is proportional to the time interval.
The current across the area is defined as the quotient of the net charge and the time interval (I = q/t).
If the result is negative, it implies a current in the backward direction.

Current in a Conductor

In a conductor, a small electric field can cause a significant acceleration of electrons due to their low mass.
In solid conductors, the current is carried by negatively charged electrons in the background of fixed positive ions.
In other types of conductors, like electrolytic solutions, both positive and negative charges can move.

Characteristics of Current

Current is measured in amperes (A) in the SI system.
An ampere is defined through magnetic effects of currents, which will be studied later.
The magnitude of currents can vary greatly, from microamperes in nerves to tens of thousands of amperes in lightning.

This quiz covers the basics of electric current, charge in motion, and its natural occurrences like lightning. It also touches on steady flow of charges in everyday devices.