18.1 A2 Level

Electric fields and field lines

7 flashcards to master this topic

Definition Flip

Define an electric field.

Answer Flip

An electric field is a region around a charged particle or object within which a force would be exerted on other charged particles or objects. Quantitatively, it is the force per unit positive charge.

Calculation Flip

What is the equation that relates force (F), charge (q), and electric field (E)?

Answer Flip

The force (F) experienced by a charge (q) in an electric field (E) is given by the equation F = qE. This equation shows the force is proportional to both the charge and the electric field strength.

Key Concept Flip

How are electric field lines used to represent an electric field?

Answer Flip

Electric field lines show the direction and relative strength of the electric field. The direction of the field line indicates the direction of the force on a positive test charge. The closer the lines, the stronger the field.

Key Concept Flip

Describe the electric field lines around a single positive point charge.

Answer Flip

The electric field lines radiate outwards from the positive charge in all directions. They are straight lines, and their density decreases with increasing distance from the charge, indicating a weaker field.

Key Concept Flip

Describe the electric field lines between two oppositely charged parallel plates.

Answer Flip

The electric field lines are parallel and equally spaced, running from the positive plate to the negative plate. This indicates a uniform electric field between the plates, except near the edges.

Key Concept Flip

What does the spacing of electric field lines indicate about the electric field strength?

Answer Flip

The closer the electric field lines are to each other, the stronger the electric field is in that region. Conversely, the farther apart the lines are, the weaker the field.

Calculation Flip

A charge of +2.0 x 10⁻⁶ C experiences a force of 0.04 N in an electric field. What is the magnitude of the electric field?

Answer Flip

Using F = qE, the electric field E = F/q = 0.04 N / 2.0 x 10⁻⁶ C = 2.0 x 10⁴ N/C. The electric field strength is 2.0 x 10⁴ Newtons per Coulomb.

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