What is the force on a charge q placed in an electric field of strength E?

What is the force on a charge q placed in an electric field of strength E?

• A. F = q / E
• B. F = E Q
• C. F = qE
• D. F = E Q^2

Answer: (C)

The force on a charge in an electric field is determined by how strong the field is and how much charge you place in it. The relationship is F = qE, where E is the electric field vector and q is the charge. This means the force grows linearly with both the charge and the field: double the charge or double the field and you double the force. The direction of the force follows the field for a positive charge and goes opposite to the field for a negative charge. The magnitude of the force is |F| = |q| |E|. Why this form makes sense: the electric field tells you how much force per unit charge the field applies, so multiplying by the actual charge gives the total force. The alternative forms with division by E or with a squared term don’t match how the field scales the force or have the wrong units, and the standard, unambiguous way to write it is the product of the charge and the field.

The force on a charge in an electric field is determined by how strong the field is and how much charge you place in it. The relationship is F = qE, where E is the electric field vector and q is the charge. This means the force grows linearly with both the charge and the field: double the charge or double the field and you double the force. The direction of the force follows the field for a positive charge and goes opposite to the field for a negative charge. The magnitude of the force is |F| = |q| |E|.

Why this form makes sense: the electric field tells you how much force per unit charge the field applies, so multiplying by the actual charge gives the total force. The alternative forms with division by E or with a squared term don’t match how the field scales the force or have the wrong units, and the standard, unambiguous way to write it is the product of the charge and the field.