Question

describe the resulting effects on the parallel beam of a horizontal mirror reflecting it across the x - axis, and then across the y - axis?

• their angles increase
• their intensity is length
• they become perpendicular
• the parallel beam remains parallel

Explanation:

When a horizontal beam reflects off the x - axis and then the y - axis, we can analyze the direction of the parallel beam. Reflection over the x - axis changes the vertical component of the direction vector, and reflection over the y - axis changes the horizontal component. But for a parallel beam, the key property is that the angle between the beam and the axes (or the direction of propagation) will be such that the beam remains parallel. Reflecting a parallel beam over perpendicular axes (x and y axes are perpendicular) will result in the beam still being parallel. The slope (steepness) is related to the angle of the beam, and reflection over x and y axes doesn't change the fact that the beam is parallel. The length of the beam segments (if we consider the path) isn't increased just by reflection, and the beam doesn't become perpendicular (unless it was at a specific angle initially, which it's not stated to be). So the parallel beam remains parallel.

Answer:

The parallel beam remains parallel.