Summer School Physical Science - CH 8 - Section II

Current that does not reverse direction is called _________.

• Direct current

• Alternating current

• Magnetic current

• Circuit current

Current that reverses direction in a regular pattern is called ____________.

• Direct current

• Alternating current

• Magnetic current

• Circuit current

An instrument that measures electric current is a ________.

• Transformer

• Motor

• Commutator

• Galvanometer

A reversing switch that rotates with the coil in an electric motor and reverses the direction of the current every half turn is called what?

• Transformer

• Motor

• Commutator

• Galvanometer

What is the function of an electric motor?

• To change electrical energy into chemical energy

• To change chemical energy into electrical energy

• To change mechanical energy into electrical energy

• To change electrical energy into mechanical energy

A galvanometer measures ___________.

• Voltage

• Magnetism

• Resistance

• Electric current

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

• Decreased

• Increased

• Unaffected

• Eliminated

2 ways to increase the magnetic force of an electro-magnet

• Increase the current flow, reduce the number of coils
• Increase the voltage, decrease the number of coils
• Increase the number of coils and the current flow
• Spread out the coils, replace iron core with rubber.

Electric current passing through a wire produces ________.

• permanent magnet
• magnetic field around wire
• compass
• geographic poles

This is a picture of a simple electromagnet. How can the electromagnet be made stronger?

• Add more coils of wire to the nail.
• Use a smaller battery.
• Reverse the poles of the magnet.
• Remove all the coils and the nail.