How does a concave mirror affect the refraction of light?

A concave mirror does not refract light; instead, it reflects light. When parallel rays of light strike a concave mirror, they are reflected inward to a focal point due to the mirror's curved surface. This reflection occurs according to the law of reflection, where the angle of incidence equals the angle of reflection. Therefore, the primary effect of a concave mirror on light is reflection, not refraction.