Ham Radio General Class Practice Test

Approximately how long is the typical sunspot cycle?

1. 8 minutes

2. 40 hours

3. 28 days

4. 11 years

The correct answer is: 11 years

The sunspot cycle, also known as the solar cycle, typically lasts about 11 years on average. This cycle represents the recurring increase and decrease in the number of sunspots, which are temporary phenomena on the Sun’s surface that indicate magnetic activity. The solar cycle affects solar radiation and electromagnetic output, impacting space weather and, consequently, radio communications on Earth. During the solar maximum phase of the cycle, the number of sunspots is at its peak, leading to increased solar activity, which can enhance radio propagation conditions, particularly on high-frequency (HF) bands. In contrast, during the solar minimum phase, the number of sunspots decreases significantly, which can diminish radio signal propagation. The other choices refer to time durations that are not relevant to the sunspot cycle. For instance, 8 minutes refers to the time light takes to travel from the Sun to Earth, 40 hours does not correlate with any known solar phenomena, and 28 days is close to the lunar cycle, which has no direct relationship to solar activity. Thus, the typical length of the sunspot cycle is correctly identified as approximately 11 years.