Unit 2a Lesson 3 Test

Match the following functions of an extension cord with their descriptions.

• Enhances the fan's power.

• The extension cord makes the fan more powerful.

• Conveys sound energy to the fan.

• The extension cord transfers electric currents from the outlet to the fan.

• Simplifies fan operation.

• The extension cord transfers sound energy to the fan.

• Conveys electrical energy to the fan.

• The extension cord makes the fan easier to operate.

Answer explanation

The extension cord transfers electric currents from the outlet to the fan, providing the necessary power for the fan to operate. This is essential for the fan to function, making this choice the correct answer.

A flow of electrical charges is known as ______.

• electrical current

• magnetic field

• voltage

• resistance

Answer explanation

A flow of electrical charges is defined as electrical current. It is the movement of electrons through a conductor, which is essential for powering devices and systems.

An electric fence used to contain cattle works by transmitting energy through a conductor creating an electric ________________.

• current

• circuit

• spark

• wave

Answer explanation

The electric fence transmits energy through a conductor, creating an electric current. This current is what delivers the shock to deter cattle, making 'current' the correct choice over 'circuit', 'spark', or 'wave'.

Tags

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In an electric circuit, a battery can act as a __.

• voltage source

• conductor

• insulator

• resistor

Answer explanation

A battery provides electrical energy by creating a potential difference, making it a voltage source. It supplies the necessary voltage to drive current through the circuit, unlike conductors, insulators, or resistors.

A conductor is a

• material that increases the number of charged particles

• material that increases the amount of electricity

• material through which electricity flows easily

• material that stops the flow of energy

Answer explanation

A conductor is defined as a material through which electricity flows easily, allowing the movement of charged particles. This distinguishes it from insulators, which impede electrical flow.

You are asked to design a product that will change electrical energy to heat energy. Choose the item you would research while developing your product.

• Hair dryer

• Alarm clock

• Ceiling fan

• Cell phone

Answer explanation

The hair dryer is designed specifically to convert electrical energy into heat energy to dry hair, making it the ideal choice for this product development. The other options do not primarily serve this function.

Tags

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Amy touched a machine called a Van de Graaf generator. When she touched the generator all of her hair on the top of her head stood up. When she removed her hand from the generator, her hair fell back to its normal state. The conclusion that can be drawn from Amy touching the generator is that (a)  

• Charged particles are being pulled
• Charged particles are being pulled
• Charged particles are being destroy
• Charged particles are being moved f

Answer explanation

When Amy touched the Van de Graaf generator, it transferred charged particles to her body, causing her hair to stand up due to the repulsion of like charges. Removing her hand allowed the charges to redistribute, returning her hair to normal.

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A switch in a circuit (a)   .

• acts as an insulator
• absorbs electricity
• allows or stops the flow of electri
• keeps the flow of electricity at a

Answer explanation

A switch in a circuit allows or stops the flow of electricity, enabling control over the circuit's operation. This is the primary function of a switch, distinguishing it from insulators or devices that absorb electricity.

Match the following electrical components with their functions in a circuit.

• Resists the flow of energy

• an inductor

• Stores energy in a magnetic field

• a capacitor

• Changes the voltage level

• a transformer

• Stores electrical energy in an electric field

• a resistor

Answer explanation

A resistor is an electrical component that opposes the flow of current, thereby resisting energy flow in a circuit. This makes 'a resistor' the correct answer, while capacitors, inductors, and transformers serve different functions.