Question

How many times stronger was the earth's magnetic field in 800 B.C.?

a. 1.5 times
b. 2 times
c. 3 times
d. 4 times

Answer 1

The answer should be c. 3 times 

Answer 2

b. 2 times

Step-by-step explanation:

The earth´s magnetic field decays approximately 10% every 150 years, so form that we can extrapole the fact that 2800 years ago it would be approximately 2 times stronger the earths magnetic field compared to the earth´s magnetic field at this time.