Question
Approximately how long does it take the increased ultraviolet and X-ray radiation from a solar flare to affect radio propagation on Earth?
Answer Options
- A) 28 days
- B) 1 to 2 hours
- C) 8 minutes
- D) 20 to 40 hours
Correct Answer: C
Explanation
A solar flare emits bursts of electromagnetic radiation, primarily in the form of X-rays and ultraviolet (UV) radiation. This radiation travels at the speed of light. Since the distance from the Sun to the Earth is approximately 93 million miles, the time it takes for this radiation to reach Earth is equal to the time it takes for light to travel that distance.
This time interval is approximately 8 minutes. Once this radiation arrives, it immediately strikes the sunlit side of the Earth, causing the ionization events that lead to a Sudden Ionospheric Disturbance (SID) and subsequent HF signal absorption.
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