Approximately how long does it take the increased ultraviolet and X-ray radiation from a solar flare to affect radio propagation on Earth?

Ultraviolet (UV) light and X-rays are forms of electromagnetic radiation. Like all electromagnetic waves, including the radio waves we use for communication and visible light, they travel at the speed of light. The Earth is approximately 93 million miles (150 million kilometers) away from the Sun. At the speed of light, it takes exactly 8 minutes for this radiation to bridge that distance. Therefore, when a solar flare erupts on the Sun, its electromagnetic effects on the Earth's ionosphere (such as a Sudden Ionospheric Disturbance) are felt just 8 minutes later. Distractors like 20 to 40 hours describe the time it takes for slower physical charged particles, like a Coronal Mass Ejection (CME), to arrive.