A uniform electric field and a uniform magnetic field exist in a region in the same direction. An electron is projected with a velocity pointed I the same direction. Then the electron will:

Options

A. be deflected to the left without increase in speed
B. be deflected to the right without increase in speed
C. not be deflected but its speed will decrease.
D. not be deflected but its speed will increase.

Explanation

To solve the problem, we need to analyze the forces acting on the electron when it is projected in a region where both a uniform electric field and a uniform magnetic field exist in the same direction.

### Step-by-Step Solution:

1. **Identify the Forces Acting on the Electron**:
- The electron is negatively charged, and it is subjected to two forces: the electric force (\( F_e \)) due to the electric field and the magnetic force (\( F_b \)) due to the magnetic field.

2. **Calculate the Electric Force**:
- The electric force acting on the electron can be calculated using the formula:
\[ F_e = qE \]
where \( q \) is the charge of the electron (which is negative) and \( E \) is the electric field strength. Since the electron has a negative charge, the direction of the electric force will be opposite to that of the electric field.

3. **Calculate the Magnetic Force**:
- The magnetic force acting on the electron can be calculated using the formula:
\[ F_b = q(v \times B) \]
where \( v \) is the velocity of the electron and \( B \) is the magnetic field strength. Since both the velocity and the magnetic field are in the same direction, the angle \( \theta \) between them is 0 degrees. Thus, the magnetic force becomes:
\[ F_b = qvB \sin(0) = 0 \]
This means there is no magnetic force acting on the electron.

4. **Analyze the Motion of the Electron**:
- Since the magnetic force is zero, the only force acting on the electron is the electric force, which is directed opposite to the motion of the electron. This will cause the electron to decelerate.

5. **Conclusion**:
- The electron will not be deflected to the left or right because there is no magnetic force acting on it. However, its speed will decrease due to the electric force acting in the opposite direction of its motion. Therefore, the correct answer is that the electron is not deflected but its speed will decrease.

### Final Answer:
The electron will not be deflected but its speed will decrease.

---