# How many turns of wire would be needed around the core of nickel to get a magnetic field of 3.43 x 10-3T with a current of 800mA?

## An electromagnet is created by wrapping 28 turns of copper wire around a 65cm long iron core. A current of 800mA is passed through the wire.

Feb 29, 2016

$N = \frac{B . l}{\setminus \mu i} = \setminus \frac{\left(3.43 \setminus \times {10}^{- 3} \setminus \quad T\right) \left(65 \setminus \times {10}^{- 2} \setminus \quad m\right)}{8.78 \setminus \times {10}^{- 5} \setminus \quad \frac{T m}{A} \setminus \times 0.8 \setminus \quad A} = 32 \setminus \quad t u r n s$