Answer:
The current required winding is

Step-by-step explanation:
We can use the expression B=μ₀*n*I-------1 for the magnetic field that enters a coil and
n= N/L (number of turns per unit length)
Given data
The number of turns n= 1200 turns
length L= 0.42 m
magnetic field B= 1*10^-4 T
μ₀=

Applying the equation B=μ₀*n*I
I= B/μ₀*n
I= B*L/μ₀*n

