At what radial distance from the center of a toroid of 300 windings does the magnitude of the magnetic field equal that found inside a solenoid that has 400 turns per meter of length? Assume that the current is the same through both devices.The magnitude of the magnetic field inside a toroid of total Ntturns and carrying a current I is, Bt=μ0NtI2πs, where s is the distance of the field point from the center of the toroid. The magnitude of the magnetic field inside a solenoid of Ns turns per unit length and carrying a current I is Bs=μ0NI. So if for a value of s, the magnetic field inside a toroid and a solenoid are the same, then the value of s can be found by using the equation, μ0NtI2πs=μ0NsI.