Chapter 7 Magnetism and Their Uses

Which of the following devices can increase or decrease the voltage of an alternating current?

• battery

• generator

• galvanometer

• transformer

The direction of the electric current in an alternating current _________.

• is constant

• is direct

• changes in a regular pattern

• changes in an irregular pattern

In order for the electromagnetic coil in a motor to keep turning, the current must

• be through an ammeter

• change direction

• periodically increase in strength

• continue in one direction

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Electric current should pass through a ______ after being transmitted by a power plant and before it enters your home.

• generator

• step-up transformer

• turbine

• step-down transformer

The ________ are regions where the magnetic force exerted by a magnet is strongest.

• cathodes

• anodes

• magnetic poles

• magnetic field lines

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The interaction between magnets and magnetic materials is called ________.

• a magnetic field

• polarity

• current

• magnetism

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Which of the following best describes how electricity is generated for homes?

• The spinning of a windmill's blades creates electric current without a generator.

• Steam pushes turbine blades in a generator which changes the mechanical energy into electrical energy.

• Water released from a dam generates electric current which is transformed into mechanical energy.

• Nuclear reactions produce an electric current inside the reaction chamber.

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Which of the following devices produces electric current?

• stereo speaker

• electric motor

• galvanometer

• generator

North poles of magnets always attract _________.

• other north poles

• negative charges

• south poles

• positive charges

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Which of the following elements is magnetic?

• aluminum

• lead

• iron

• tin

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