The voice coil in your stereo speaker's woofer has 1200 tightcircular turns (in the plane), a diameter of 5.1cm, and a coilresistance of 7.4. The stereo amplifier sends in a singnalcurrent into the woofer (voice coil) at a specific point in timesuch that the potential difference across the coil's leads is2.6volts. Determine the magnitude (in mT) of the magnetic fieldB, at the center of the voicecoil. The voice coil in your stereo speaker's woofer has 1200 tightcircular turns (in the plane), a diameter of 5.1cm, and a coilresistance of 7.4. The stereo amplifier sends in a singnalcurrent into the woofer (voice coil) at a specific point in timesuch that the potential difference across the coil's leads is2.6volts. Determine the magnitude (in mT) of the magnetic fieldB, at the center of the voicecoil.
Explanation / Answer
Magnetic field at the center of voice coil (a solenoid)is B = 0* n * I n = no. ofturns perunit length = 1200 /L I = V/R = 2.6/7.4 = 0.351 A B = 4 * * 10-7 * 1200 * 0.351 / L = 5.29* 10-4 /L = 0.529/ L mT Substitute the value of length of coil(L) to get answer.