16185477
Description
Flashcards by Daniel Davis, updated more than 1 year ago
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Created by Daniel Davis
over 5 years ago
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| Question | Answer |
| How is a magnetic field creates around a wire? | It is created when there is electric current through a wire. |
| What creates a magnetic field around a wire? | When there is an electric current through a wire it creates a magnetic field around the wire? |
| What do plotting compasses show? | They show the shape & direction of the magnetic field. |
| What happens when direction of current changes? | The direction of magnetic field changes if direction of current changes. |
| What is the magnetic field around a single & two wires. | Magnetic field around single wire is circular. Two wires are close together magnetic fields overlap. |
| How do you make an electromagnet? | Wrapping a wire around an iron bar. |
| What happens when there is an electric current through the wire of an electromagnet? | The electromagnet has a magnetic field similar to the magnetic field of a bar magnet? |
| How is the magnetic field of an electromagnet formed? | The magnetic fields from the two wires are in opposite directions so the two fields cancel each other out. |
| How is the magnetic field around a coil of wire formed? | Caused by combination of fields of all the parts of the wire combined. |
| What happens to the wires in a coil? | They're close together. Inside the coil, the magnetic fields from both sides of the coil are in the same direction. The two fields reinforce each other. The magnetic field is strong and uniform inside the coil. A uniform field is the same strength and direction everywhere. |
| What happens outside the coil? | The fields from each side of the coil are in opposite directions. Fields partly cancel each other out. So, field is weaker outside the coil. |
| What is a solenoid? | A coil of wire where it is has a strong, uniform magnetic field inside the coil & weaker field outside the coil. Solenoids often have iron cores because this makes the magnetic field stronger. |
| What is flemings left hand rule? | Shows the relationship between directions of current, force and magnetic field First Finger = Force Second Finger = Current Thumb = Thumb Movement |
| What is the motor effect? | When you put the wire with a magnetic field into a field of another magnet the two fields affect each other and wire experiences a force. To work out direction of force we use Fleming's left hand rule |
| What is electromagnetic induction? How to increase. | A voltage is produced when a magnet moves into a coil of wire. Can be increased by moving magnet faster & adding more turns to the coil. |
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