The electron has a magnetic moment, so you can do magnetic resonance measurements on substances with unpaired electron spins. The electron has a magnetic moment \(\mu=9.3 \times 10^{-24} \mathrm{~J} / \mathrm{T}\). A sample is placed in a solenoid of length \(15 \mathrm{~cm}\) with 1200 turns of wire carrying a current of \(3.5 \mathrm{~A}\). A probe coil provides radio waves to "flip" the spins. What is the necessary frequency for the probe coil?