A free negative charge released in an electric field will
A accelerate in the direction opposite the electric field,
B accelerate along a circular path.
C accelerate in a direction perpendicular to the electric field, remain at rest.
D accelerate in the same direction as the electric field is pointing.
The correct answer and explanation is :
The correct answer is:
A) accelerate in the direction opposite the electric field.
Explanation:
When a negative charge is placed in an electric field, the direction of the electric force acting on the charge is opposite to the direction of the electric field. This occurs because the electric field is defined as the force that a positive test charge would experience. A negative charge, however, experiences a force in the opposite direction to the electric field.
Let’s break down the key points:
- Electric Field and Force:
The electric field ($E$) exerts a force ($F$) on any charged object placed in it. The force experienced by a charge is given by Coulomb’s law: $$
F = qE
$$ where:
- $q$ is the charge of the object,
- $E$ is the electric field. If the charge is positive, the force will be in the direction of the field. However, if the charge is negative, the force will be in the opposite direction to the electric field.
- Acceleration:
According to Newton’s second law of motion ($F = ma$), where $m$ is mass and $a$ is acceleration, the force causes the charge to accelerate. Since a negative charge experiences force in the opposite direction to the electric field, it will accelerate in that opposite direction. - What This Means in Context:
A negative charge released in an electric field will move in the opposite direction of the field’s arrows. This can be visualized by imagining the electric field lines as pointing in a particular direction (say, from positive to negative), and a negative charge moving in the opposite direction. - Other Options:
- B) A circular path would occur under a magnetic field or centripetal force, not an electric field.
- C) The charge would not remain at rest because it experiences an electric force.
- D) A negative charge accelerates in the opposite direction to the field, not in the same direction.
Therefore, the correct answer is A because a negative charge moves opposite to the direction of the electric field lines.