We can answer this problem using Ampere’s Law:
Bh = μoNI
Where:
B = Magnetic Field
h = coil length
μo = permeability =4π*10^-7 T·m/A
N = number of turns
I = current
It is given that B=0.0015T, I=1.0A, h=10 cm = 0.1m
Use Ampere's law to find # turns:
Which can be rewritten as:
N = Bh/μoI
N = (0.0015)(0.1)/(4π*10^-7)(1.0)
N = 119.4
Answer: 119.4 turns