Answer:
I = 3.81 x 10⁴ A
Step-by-step explanation:
The magnetic field of a solenoid must be equal to the field of earth:

where,
I = current passing through solenoid = ?
μ = permeability of free space = 4π x 10⁻⁷ N/A²
n = no. of turns per unit length =
= 1086.96 /m
Therefore,

I = 3.81 x 10⁴ A