The steady or initial phase of the magnetic storms is

A. preceded by storm sudden commencement

B. magnetic storm at middle and low altitudes

C. a sharp increase of the field

D. None of the above

Answer: Option A

Solution(By Examveda Team)

During these few minutes--the sudden-commencement phase--of the storm, the horizontal component of the geomagnetic field increases suddenly over the entire globe. The increase persists for two to six hours and is classified as the initial phase of the storm.