Asseration : Power of a constant force is also constant.
Reason : Net constant force will always produce a constant acceleration.

Options

A. If both Assertion and Reason are true and the Reason is correct explanation of the Assertion.
B. If both Assertion and Reason are true and the Reason is not the correct explanation of the Assertion.
C. If Assertion is true, but the Reason is false
D. If Assertion is false but the Reason is true.

Explanation

To solve the question, we need to analyze the assertion and the reason provided:

**Assertion:** Power of a constant force is also constant.

**Reason:** Net constant force will always produce a constant acceleration.

### Step-by-Step Solution:

1. **Understanding Power:**
- Power (P) is defined as the rate at which work is done. Mathematically, it can be expressed as:
\[ P = F \cdot v \]
where \( F \) is the force and \( v \) is the velocity.

2. **Constant Force and Acceleration:**
- According to Newton's second law, if a constant force \( F \) is applied to an object of mass \( m \), it produces a constant acceleration \( a \):
\[ F = m \cdot a \quad \Rightarrow \quad a = \frac{F}{m} \]
- Since both \( F \) and \( m \) are constants, \( a \) is also constant.

3. **Velocity as a Function of Time:**
- If the object starts from rest (initial velocity \( u = 0 \)), the velocity \( v \) after time \( t \) can be expressed as:
\[ v = u + at = 0 + at = at \]
- Substituting \( a \) in terms of \( F \):
\[ v = \frac{F}{m} \cdot t \]

4. **Substituting Velocity into Power Equation:**
- Now, substituting \( v \) back into the power equation:
\[ P = F \cdot v = F \cdot \left(\frac{F}{m} \cdot t\right) = \frac{F^2}{m} \cdot t \]

5. **Analyzing Power Over Time:**
- From the equation \( P = \frac{F^2}{m} \cdot t \), we see that power is proportional to time \( t \). As time increases, power also increases.
- Therefore, the power is not constant; it varies with time.

6. **Conclusion:**
- The assertion that "Power of a constant force is also constant" is **false**.
- The reason that "Net constant force will always produce a constant acceleration" is **true**.

### Final Answer:
- Assertion is false, Reason is true. Hence, the correct option is option 4.