8TH GRADE · CHARGE AND ELECTRIC FIELD
Charge interaction and electric field
Coulomb's law, tension, benefits and dangers of static electricity.
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
Coulomb's law
The force of interaction between point charges is proportional to the product of the charge moduli and inversely proportional to the square of the distance.
The direction of the force is along the line between the charges; the sign of the charges determines attraction or repulsion.
Electric field
A form of matter created by electrical charges and exerting a force on other charges.
The voltage shows the force per unit positive test charge, and the lines are directed from plus to minus.
Static electricity
The accumulated charge can produce a useful particle attraction or a dangerous spark discharge.
Electrostatic precipitators use a field to purify the air, and grounding reduces the risk of ignition of vapors by a static spark.
Physical quantities
Electric power
The force of interaction between the two electric charges under consideration.
Unit: newton ·
Field strength
Electric field strength per unit positive charge.
Unit: newton per coulomb ·
Distance between charges
Distance between point charges in Coulomb's law.
Unit: meter ·
Electrostatic constant
Coulomb's law coefficient for the selected medium and units.
Unit: newton square meter per square pendant ·
Lesson formulas
Coulomb's law
The force modulus is equal to the coefficient multiplied by the product of the charges and divided by the square of the distance.
Field strength
The intensity is equal to the field strength on the positive test charge divided by that charge.
Related formulas
The same formulas in the reference, with symbols and units.
Tasks on the topic
Statements, answer options and the walkthrough.