Explore the principles of magnetic fields generated by electric currents in this comprehensive physics lecture. Delve into the magnetic fields produced by straight wires, current loops, and solenoids. Learn how to calculate magnetic fields for various configurations, including parallel wires carrying opposite currents. Tackle practical examples, such as determining the number of wire turns needed in a solenoid to produce a specific magnetic field strength. Enhance your understanding of electromagnetism through detailed explanations and problem-solving techniques.