What is the difference between linear and circular polarization? Sketch the three-dimensional E- and H- fields to support the explanation.

Polarization refers to the orientation of the oscillations in a transverse wave. In electromagnetic waves, both the electric field (E-field) and magnetic field (H-field) are oscillating and perpendicular to each other.

1. Linear Polarization: In linear polarization, the electric field vector (E-field) oscillates in a single plane perpendicular to the direction of propagation. The magnetic field vector (H-field) is perpendicular to this plane. If you were to plot the E-field vector over time at a fixed point in space, it would form a straight line.

2. Circular Polarization: In circular polarization, the electric field vector (E-field) rotates in a circle around the direction of propagation, maintaining a constant amplitude. The magnetic field vector (H-field) is perpendicular to this circle. If you were to plot the E-field vector over time at a fixed point in space, it would form a circle.

Sketching the fields:

1. Linear Polarization: Imagine a wave moving along the z-axis. For linear polarization, the E-field might oscillate along the x-axis. At any given point along the z-axis, the E-field vector would move back and forth along the x-axis. The H-field would then oscillate along the y-axis.

2. Circular Polarization: Again, imagine a wave moving along the z-axis. For circular polarization, the E-field vector would rotate in the x-y plane as the wave propagates. At any given point along the z-axis, the E-field vector would move in a circular path in the x-y plane. The H-field would still oscillate along the y-axis, but 90 degrees out of phase with the E-field.

Please note that this is a text-based platform and I'm unable to provide sketches. However, you can easily find diagrams illustrating these concepts with a quick internet search.