Magnetic Field Around a Coil?

📌 CONCEPT: The magnetic field strength around a coil depends on the current flowing through it, the number of turns, and the distance from the coil's center, as described by the formula B ∝ (NI)/r, where B is the magnetic field strength, N is the number of turns, I is the current, and r is the distance from the coil's center.

📐 RULE / FORMULA: The magnetic field strength around a coil is directly proportional to the current flowing through it, the number of turns, and inversely proportional to the distance from the coil's center, as described by the formula B ∝ (NI)/r.

💡 WORKED EXAMPLE: If a coil has 50 turns and a current of 2A, and at a distance of 10cm, the magnetic field strength is 5 x 10^-6 T, doubling the number of turns will result in a new magnetic field strength of (2 * 50) / (50) * 5 x 10^-6 T = 10 x 10^-6 T.

⚠️ COMMON MISTAKE: Students often forget to consider the effect of the number of turns on the magnetic field strength, assuming that only the current and distance are relevant.