Answer:
The current required winding is
![2.65*10^-^2 mA](https://img.qammunity.org/2021/formulas/physics/college/164943x1169antj13f34svpq3spdcfdlph.png)
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=
![4\pi*10^-^7 T.m/A](https://img.qammunity.org/2021/formulas/physics/college/t1oads5bq3obuqykcj33crf9zc90tu5230.png)
Applying the equation B=μ₀*n*I
I= B/μ₀*n
I= B*L/μ₀*n
![I= (1*10^-^4*0.42)/(4\pi*10^-^7*1.2*10^3 )](https://img.qammunity.org/2021/formulas/physics/college/1rcgrwd401m9gwbo48i17y340v4to1b1z2.png)
![I= 2.65*10^-^2 mA](https://img.qammunity.org/2021/formulas/physics/college/prmpxwr3s9yrhd6yi3qohsy97padjiodkg.png)