Physics

Problem

Which statement correctly describes the relationship between the angle of incidence

i

and the angle of reflection

r

for light striking a plane mirror? a)

i + r = 90^{\circ}

i = 90^{\circ}-r

i = r

i = 2r

Intuitive explanation

The law of reflection is one of the most fundamental rules in optics, and it's beautifully simple: the angle of incidence and angle of reflection are always equal. The key insight is that both angles are measured from the same reference line—the normal (an imaginary perpendicular to the mirror's surface)—not from the mirror itself. This equal-angle relationship holds regardless of the mirror's orientation or the light's color, making it a universal principle you can rely on in any reflection problem.

Intuitive explanation

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