Exam 3

Question 1

Motion or kinetic energy of the molecules in a substance

Answer 1

Heat

Question 2

What has more energy—a cold or a hot object?

Answer 2

Hot object—it has more kinetic energy

Question 3

Thermal energy flows spontaneously (without external assistance) from a higher-temperature object to a lower temperature object. It will not spontaneously flow the other way

Answer 3

The second law of thermodynamics

Question 4

The total energy of an isolated system is conserved. Energy may be transferred from one part of the system to another, and energy may be transformed from one form to another, including thermal energy, but the total value of the energy is conserved

Answer 4

First law of thermodynamics

Question 5

Any device that uses thermal energy to do

work is called

Answer 5

Heat engine

Question 6

In one cycle of operation a heat engine consumes 1500 J of thermal energy and performs 400 J of work. What is the amount of energy that is exhausted in each cycle? What is the efficiency of this engine?

Answer 6

1100 J

0.27 or 27%

Question 7

A substance in which electric charge can flow readily

Answer 7

Conductor

Question 8

A substance in which electric charge does not flow easily

Answer 8

Insulator

Question 9

The flow of charged particles

Answer 9

Electric current

Question 10

A current that reverses its direction as time goes by

Answer 10

Alternating current

Question 11

A time-changing magnetic field produces a time-changing electric field

Answer 11

Faraday’s Law of Induction