If a charged particle `(+q)` is projected with certain velocity parallel to the magnetic field, then it will

Options

A. trace helical path
B. trace circular path
C. continue its motion without any change
D. come to rest instantly

Explanation

To solve the question, we need to analyze the behavior of a charged particle when it is projected parallel to a magnetic field.

### Step-by-Step Solution:

1. **Understanding the Force on a Charged Particle**:
The force \( F \) acting on a charged particle moving in a magnetic field is given by the equation:
\[ F = q \cdot v \cdot B \cdot \sin(\theta) \]
where:
- \( q \) = charge of the particle,
- \( v \) = velocity of the particle,
- \( B \) = magnetic field strength,
- \( \theta \) = angle between the velocity vector and the magnetic field vector.

2. **Identifying the Angle**:
In the case where the charged particle is projected parallel to the magnetic field, the angle \( \theta \) is \( 0^\circ \).

3. **Calculating the Sine of the Angle**:
The sine of \( 0^\circ \) is:
\[ \sin(0^\circ) = 0 \]

4. **Substituting into the Force Equation**:
Substituting \( \sin(0^\circ) \) into the force equation gives:
\[ F = q \cdot v \cdot B \cdot 0 = 0 \]

5. **Conclusion on the Motion of the Particle**:
Since the magnetic force \( F \) is zero, there is no force acting on the charged particle. Therefore, the particle will continue its motion without any change in velocity or direction.

### Final Answer:
The charged particle \( (+q) \) will continue its motion without any change.

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