11 Years
Usually sunspot and solar flare cycles vary. But the average duration occurs every 11 years, sometimes 9-14 years as well.
Answer:

Explanation:
The minimum distance for takeoff is:




Answer:
B is the answer
Explanation:
When A is divided by 7x, it multiplies to0.81
The answer is: to determine that electric beams in cathode ray tubes were actually made of particles
I hope this helps!