# What does electromagnet mean

## Understand physics 4, textbook

41 Electricity determines our lives  Learning objective check 9, page 88 3. What does the power of an electromagnet depend on? A simple electromagnet (Fig. 41.1) connects a coil (insulated wire wrapped around a nail) to a 9V battery. Check the magnetic attraction without and with the nail (= iron core) with a magnetic needle and with small iron nails. The coil with the nail (= iron core) has a greater magnetic force. The elementary magnets in the nail are organized by the force field of the coil. The magnetic fields of the coil and the nail work together. M An electromagnet is a current-carrying coil with an iron core. The magnetic force is reinforced by the iron core. The stronger electromagnet (Fig. 41.2) Three different coils (e.g. 300, 600 and 1200 turns) with an iron core are compared as electromagnets. Use direct current (up to 12 volts). Compare the pull. What happens if you change the voltage or amperage? The more wire turns the coil has and the greater the current, the stronger the electromagnet. The larger number of turns means a larger total length of the insulated wire of the coil. M The magnetic force of the electromagnet increases with the strength of the current and the number of turns of wire in the coil. 4. How does a permanent magnet affect a current-carrying conductor? The coil swings (Fig. 41.3). Set up the experiment according to Fig. 41.3. Connect the red cable to the positive pole and the blue cable to the negative pole of a student power supply unit. How does the coil behave? Change the direction of the current and turn the magnet over. What do you see A coil through which current flows itself generates a magnetic field. It moves in the magnetic field of the permanent magnet, since both magnetic fields interact with each other (see Fig. 41.6). M A current-carrying conductor is set in motion in the force field of a permanent magnet. V4 V5 V6 41.1 A simple electromagnet 41.2 The stronger electromagnet 41.4 Coil and coil with iron nail (= iron core) 41.5 The high-speed train is moved by electromagnets. 41.6 The three-finger rule shows the direction of deflection of a current-carrying conductor. U - cause (direction of current) W - effect (direction of movement) V - mediation (direction of the magnetic field) iron nail eg 30 turns of insulated wire 41.3 The coil swings. For testing purposes only - property of the publisher öbv