Motion of a Particle Revolving Along a Circle

When a particle revolves along a circle with a uniform speed, the motion of the particle is considered to be two-dimensional.

Explanation:
One-dimensional Motion:
One-dimensional motion refers to the motion of an object along a straight line. In this type of motion, the object can only move forward or backward. The position of the object is described by a single coordinate, usually denoted as x.

Two-dimensional Motion:
Two-dimensional motion refers to the motion of an object in a plane. In this type of motion, the object can move in any direction within the plane. The position of the object is described by two coordinates, usually denoted as (x, y) or (r, θ) in polar coordinates.

Particle Revolving Along a Circle:
When a particle revolves along a circle, it moves in a curved path. The motion of the particle can be described in terms of its position along the circumference of the circle.

Uniform Speed:
When the particle moves with a uniform speed, it covers equal distances in equal intervals of time. This means that the particle takes the same amount of time to travel from one point to another along the circumference of the circle.

Motion of the Particle:
The motion of the particle revolving along a circle with a uniform speed is two-dimensional for the following reasons:

1. The particle moves along the circumference of the circle, which is a curved path in a plane.
2. The position of the particle can be described using two coordinates - the radius of the circle (r) and the angle (θ) it makes with a reference line.

Conclusion:
Hence, the correct answer is option 'B' - the motion of the particle is two-dimensional when it revolves along a circle with a uniform speed.