8TH GRADE · ELECTRIC CURRENT
Electric current and circuit
Conditions for the existence of current, sources, direction and effects of current.
The entire theory of the lesson is collected here; you can read it without an account. In interactive mode, the same theory appears as cards, followed by questions. with checking the answer and task, and progress is saved.
Basic Concepts
Electric current
Ordered motion of charged particles that exists in the presence of free carriers and an electric field.
In metals, the carriers are electrons, and the conditional direction of the current is opposite to their directional movement.
Current source
A device that separates charges by converting chemical, mechanical, light or other energy.
The source maintains a potential difference, a closed circuit provides a path for charges, and its circuit can be read according to the standard symbols of elements.
Actions of electric current
The passage of current can cause heat, a magnetic field, chemical changes and an effect on living tissue.
The observed action allows the detection of current and is the basis of heaters, motors and electrolysis.
Physical quantities
Past charge
The charge passed through the cross section of the conductor during the selected time.
Unit: pendant ·
Charge transit time
Duration of ordered movement of a charge through a cross section.
Unit: second ·
Lesson formulas
Electric current
The current strength is equal to the transmitted charge divided by the transit time.
Related formulas
The same formulas in the reference, with symbols and units.
Tasks on the topic
Statements, answer options and the walkthrough.