A positively charged particle is released from rest in a uniform electric field. The electric potential energy of the charge.

Options

A. remains a constant because the electric field is uniform.
B. increases because the charge moves along the electric field.
C. decreases because the charge moves along the electric field.
D. decreases because the charge moves opposite to the electric field.

Explanation

To solve the problem regarding the electric potential energy of a positively charged particle released from rest in a uniform electric field, we can follow these steps:

### Step 1: Understand the Concept of Electric Field
An electric field (E) is a region around a charged particle where other charged particles experience a force. The direction of the electric field is defined as the direction of the force that a positive charge would experience.

**Hint:** Recall that the electric field points away from positive charges and towards negative charges.

### Step 2: Analyze the Movement of the Charged Particle
When a positively charged particle is released from rest in a uniform electric field, it will experience a force in the direction of the electric field. This means that the particle will start to move in the direction of the electric field.

**Hint:** Remember that a positively charged particle moves in the direction of the electric field lines.

### Step 3: Relate Electric Potential and Electric Field
The relationship between electric potential (V) and electric field (E) is given by the equation:
\[ E = -\frac{dV}{dx} \]
This indicates that the electric field is related to the rate of change of electric potential with respect to position.

**Hint:** Consider how potential changes as you move through the electric field.

### Step 4: Determine the Direction of Potential Change
As the positively charged particle moves in the direction of the electric field, it moves from a region of higher electric potential to a region of lower electric potential. This means that the potential (V) decreases as the particle moves.

**Hint:** Think about how potential energy is affected when moving from high to low potential.

### Step 5: Analyze the Change in Electric Potential Energy
The electric potential energy (U) of a charge in an electric field is given by:
\[ U = qV \]
where \( q \) is the charge and \( V \) is the electric potential. Since the particle is moving to a region of lower potential, the electric potential energy of the charge decreases.

**Hint:** Remember that potential energy decreases when moving to lower potential for a positive charge.

### Conclusion
Thus, when a positively charged particle is released from rest in a uniform electric field, the electric potential energy of the charge decreases as it moves along the direction of the electric field.

**Final Answer:** The electric potential energy of the charge decreases.