Chapter 6

What must the source be supplying in an electric circuit for the resistors to use energy to do work?

• Power

• Voltage

• Energy

• Current

Answer explanation

The source must supply energy in an electric circuit for the resistors to do work.

What is the next step after understanding the relationships among voltage, current, and resistance in an electric circuit?

• Calculating the efficiency

• Calculating the kilowatt hour

• Calculating the energy and power associated with the source and resistors

• Understanding the heating effect of current

Answer explanation

The next step after understanding the relationships among voltage, current, and resistance is to calculate the energy and power associated with the source and resistors.

Which term is defined by its ability to do work or cause change?

• Efficiency

• Watt

• Power

• Kilowatt hours

Answer explanation

Power is defined as the ability to do work or cause change. It is a measure of how quickly work is done or energy is transferred.

What will you be able to calculate regarding a resistor after completing this chapter?

What is the unit of measurement for energy that is listed in the key terms?

• Watt

• Horsepower

• Kilowatt hours

• British thermal unit (BTU)

Answer explanation

The unit of measurement for energy listed in the key terms is Kilowatt hours. It is a concise and correct choice.

After studying this chapter, you should be able to perform calculations based on equations relating which of the following sets of physical quantities?

What outcome is associated with defining efficiency in terms of energy and power?

• Understanding the cost of electrical energy

• Calculating the efficiency of a device

• Measuring the speed of an electrical current

• Determining the resistance of a material

Answer explanation

Efficiency is defined as the ability to calculate the efficiency of a device in terms of energy and power. It helps understand the cost of electrical energy and highlights the correct choice.

What is work a transfer of, as explained in Section 2-7?

• Energy from one location to another

• Heat from one object to another

• Mass from one system to another

• Electricity from one circuit to another

Answer explanation

Work is a transfer of energy from one location to another.

In the context of energy conversions, what does the generator do in Figure 6-1?

• Converts mechanical energy into heat energy

• Converts electrical energy into mechanical energy

• Converts heat energy into electrical energy

• Converts mechanical energy into electrical energy

Answer explanation

The generator in Figure 6-1 converts mechanical energy into electrical energy. It is responsible for generating electricity.

According to the example provided, what percentage of the electric energy supplied to the motor is lost as heat when raising an elevator car?

• 5%

• 10%

• 20%

• 25%

Answer explanation

According to the example, 10% of the electric energy supplied to the motor is lost as heat when raising an elevator car.