Electricity and Circuits

In order to turn on the light, a piece of wire needs to be connected from —

• A to D

• B to C

• A to C

• C to D

Laundry in a clothes dryer often becomes charged with static electricity while drying. Which of these best explains why a clothes dryer often generates static electricity?

• Heat from the dryer charges the air and produces lightning.

• Short circuits in the dryer charge the laundry.

• Electrons are transferred as clothes rub against each other in the dryer.

• Clothes with metal pieces conduct electricity in the dryer.

Which of the following is an example of static electricity?

• A balloon sticks to a wall after it is rubbed with a piece of wool.

• A magnet sticks to a refrigerator door made of metal.

• A dry-cell battery connected to wires lights up a light bulb.

• A light switch that is turned on runs a ceiling fan.

An electric light bulb is hot to the touch because —

• evaporation causes an object to heat up

• its magnetic field produces a large amount of heat

• current passing through it produces heat

• its chemical reactions produce heat

A group of campers travels to a cabin which has no electrical power. In order to provide the power for a heater and lights, which device would be appropriate?

• A resistor

• An insulator

• A generator

• A voltmeter

Electric bills are calculated based on the amount of energy consumed. The consumption is measured in units of —

• megavolt minutes

• newton meters

• kilowatt hours

• millijoule seconds

Which system shows a transformation from chemical to electrical and light energy?

• A display of fireworks in the night sky.

• A car battery causes the headlights to shine.

• An avalanche rolls down a steep mountain.

• A candle burns and lights up the room.

Insulation materials reduce heat loss because they —

• promote convection

• are poor conductors

• reduce evaporation

• block out the sun