Ch 6 Review - Electricity

Which of the following materials is a good conductor of electricity?

• Rubber

• Copper

• Wood

• Glass

Answer explanation

Copper is a metal known for its excellent electrical conductivity, making it a good conductor of electricity. In contrast, rubber, wood, and glass are insulators and do not conduct electricity well.

What is the primary function of an insulator in an electrical circuit?

• To allow the flow of electric current

• To prevent the flow of electric current

• To increase the voltage

• To decrease the resistance

Answer explanation

The primary function of an insulator in an electrical circuit is to prevent the flow of electric current. This property is essential for ensuring safety and controlling the flow of electricity.

According to Ohm's Law, what is the formula to calculate voltage?

Answer explanation

According to Ohm's Law, voltage (V) is calculated using the formula V = I × R, where I is the current and R is the resistance. This makes the first choice the correct answer.

If a circuit has a current of 3 A and a resistance of 4 Ω, what is the voltage across the circuit?

• 7 V

• 12 V

• 1.33 V

• 0.75 V

Answer explanation

Using Ohm's Law (V = I × R), where I = 3 A and R = 4 Ω, we calculate V = 3 A × 4 Ω = 12 V. Therefore, the voltage across the circuit is 12 V.

Which type of circuit allows multiple paths for electricity to flow?

• Series Circuit

• Open Circuit

• Parallel Circuit

• Closed Circuit

Answer explanation

A parallel circuit allows multiple paths for electricity to flow, meaning if one path is interrupted, current can still flow through other paths. In contrast, a series circuit has only one path.

In a series circuit, if one component fails, what happens to the entire circuit?

• The circuit continues to work

• The circuit stops working

• The voltage increases

• The current increases

Answer explanation

In a series circuit, all components are connected in a single path. If one component fails, it breaks the circuit, causing the entire circuit to stop working. Therefore, the correct answer is that the circuit stops working.

How is electrical energy typically measured?

• In volts

• In amperes

• In watts

• In ohms

Answer explanation

Electrical energy is typically measured in watts, which represent the rate of energy transfer. Volts measure electric potential, amperes measure current, and ohms measure resistance, but watts quantify energy usage.

What device is used to measure electrical energy consumption in households?

• Voltmeter

• Ammeter

• Wattmeter

• Electric meter

Answer explanation

The electric meter is specifically designed to measure electrical energy consumption in households, providing accurate readings of usage over time. Other devices like voltmeters and ammeters measure voltage and current, respectively, but not energy.

What natural phenomenon is a large-scale example of static electricity discharge?

• Earthquake

• Lightning

• Tornado

• Tsunami

Answer explanation

Lightning is a natural phenomenon caused by the discharge of static electricity in the atmosphere, making it a large-scale example of static electricity discharge. Other options like earthquakes and tsunamis are unrelated.

Tags

NGSS.MS-PS3-5

Which of the following best describes how lightning is formed?

• It is caused by the collision of warm and cold air masses

• It is a result of the Earth's magnetic field

• It occurs when there is a separation of the negative and positive charges within the storm cloud

• It is produced by the sun's rays

Answer explanation

Lightning is formed when there is a discharge of static electricity in the atmosphere, typically during thunderstorms, as electrical charges build up and are released, creating a bright flash of light.