Ch. 18 Electricity & Magnetism Lesson 1 – Electricity

On a cold, winter day, you walk across a wool carpet & then touch a metal doorknob. Predict what will happen. Explain why. 10 pts. You may feel a small shock because of static electricity. Walking on a wool carpet transfers electrons from the carpet to your body. You acquire an overall negative charge, which will attract positive charges in the doorknob.

A circuit in which electrical current flows along a single path Series circuit

What kind of circuit is this? How does it work? It is a parallel circuit. In a parallel circuit, current can follow more than one path. When a resistor in one of the paths breaks, current can still flow along the other paths.

Parallel VS. Series – In Christmas lights What type of circuit should be used for this electrical device? 10 pts. It should be a parallel circuit because if one bulb broke, the rest would remain on. Also the bulbs would shine more brightly than if a series circuit were used.

How do power plants increase or decrease the voltage of electricity? 10 pts. Power plants use one kind of transformer to increase voltage before sending currents through power lines. At the other end, currents pass through another type of transformer that reduces the voltage.

Electric charges do not move easily through a(n) _______________________.

Why is it dangerous to have electric appliances near you when you are taking a bath? 10 pts. Water is an excellent conductor of electricity. If an electrical appliance was dropped into the water, the electricity could travel from the appliance to your body & electrocute you.

A magnet is also a magnetic ______________ because it has two poles.

This drawing shows the region around a magnet called the _____________ ________

How could you create an electromagnet? 5 pts. Wrap insulated wire around an iron bar, & send electricity through the wire. The bar becomes a magnet.

What is shown in the picture? Explain how it works. It is an electromagnet. Electricity from the battery flows through the coiled wire. The nail will remain magnetic as long as current flows through the wire.

How does a AC electric motor work? 10 pts. An insulated wire is coiled around the armature. When current moves through the wire coil, the armature becomes an electromagnet. Attraction & repulsion between the armature’s poles and the poles of the permanent magnet cause the armature to rotate.

Name three types of data storage systems that are based on magnetic materials. 5 pts. Video & audio recordings Credit cards Computer hard drives

Definitions for test Electricity Static electricity Current electricity Conductor Electric generator Electric motor