Chapter 7 and 8 Review

Electricity and Magnetism

What type of circuit is represented in the following diagram?

a. parallel circuit

b. open circuit

c. series circuit

d. electron circuit

Parallel Circuit

Parallel Circuit- 2 or MORE paths

Series Circuit

Series Circuit- ONE path

Which type of electricity is demonstrated in the picture on the right?

a. static electricity

b. current electricity

c. circuit electricity

d. current circuit

Static Electricity

Static Electricity- the accumulation of excess electric charges on an object. Transfer of electrons!

Any substance that can attract iron or other magnetic materials is called a/an

a. conductor

b. insulator

c. magnet

d. electron

The current that flows in an electric circuit carries ____.

a. chemical energy

b. mechanical energy

c. thermal energy

d.electrical energy

A transformer that increases voltage is a ____.

a. resistance transformer

b. step-up transformer

c. step-down transformer

d. voltage motor

In the United States, power lines can carry power voltages as high as 750,000 V, a step-down transformer reduces the voltage to ____ for home use.

a. 60 V

b. 120 V

c. 60 Hz

d. 120 Hz

A step-down transformer is used to reduce the voltage carried by power lines from 750,000 V to

120 V, so that we can safely use it in our home!

A dry-cell battery produces ____.

a. an alternating current

b. the same current that a generator produces

c. a direct current

d. both direct and alternating current

Direct Current (DC)- electrons move from the negative terminal

to the positive terminal. ONE direction!

Alternating Current (AC)- electrons change direction at regular intervals in a circuit. (Alternating direction)

• The magnetic force of a magnet is ____.

a. the same at all parts of the magnet

b. strongest at the poles

c. strongest at the center

d. weakest at the poles

The magnetic force is STRONGEST at the poles.

N S

Nor

th P

ole

Sou

th P

ole

In this circuit, how much current flows through the lightbulb?

a.0.75 ampb.1.50 ampsc.2.0 ampsd.3.0 amps

V

RI

1.5 V

2.0 ohms

0.75 amps

The bulb will light when a current supplied by at least one 1.5 V battery is available. Which circuit will fail to light the bulb?

In order to create static electricity, two objects must rub together. What is the only particle rubbed off of one object and onto the other?

a. protons

b. neutrons

c. electrons

Remember….

Electricity is the flow or movement of ELECTRONS from one place to another.

e

ee

ee e e

Which items are considered to be safety devices that stop the flow of current during an overload?

a. batteries and fuses

b. batteries and circuit breakers

c. bulbs and circuit breakers

d. fuses and circuit breakers

Fuse & Circuit Breaker Prevents electrical circuits from

overheating

The strength of a magnetic force in an electromagnet is ________ by increasing the current through the coil.

a. unaffected

b. increased

c. decreased

d. eliminated

• The strength of an electromagnet can be INCREASED by

– Increasing the current

– More turns in coil of wire

– Bigger iron core

25. Which pair of magnets would result from cutting this magnet in half?

What is the voltage (VOLTS- V) of a circuit that contains 3A of current and a 4-ohm bulb?

V

RI3 A4

Ohms

12 V

a.12 V

b. 1.33 V

c. 0.75 V

The voltage of the circuit is 10V. What current flows through a 5-watt resistor?

P

VI 10 V

5 W

0.5 A

a. 50A

b. 0.5A

c. 2A

LET’S DO IT AGAIN !!!!!!!