Question 1

Large amounts of material can often be seen rising from the cooling towers often seen at steam- electric power plants. These emissions are mostly

Accepted Answer

The emissions from cooling towers at steam-electric power plants are primarily water vapor, which is released as steam. This is a result of the cooling process where water is used to condense steam back into liquid form, and some of it evaporates into the atmosphere.

Question 2

Which method of fueling your car is likely to be more energy efficient, and why: gasoline used in a standard car engine or electricity taken from a coal- fueled generating plant and stored in lightweight car batteries? Assume that the batteries convert electricity to work at 100% efficiency, and that electricity is transported from the power plant to the car at 100% efficiency.

Accepted Answer

Coal-fired generating plants generally operate at higher efficiencies than car engines, which are limited by the second law of thermodynamics and typically have lower thermal efficiencies.

Question 3

Which of these uses thermal energy to do work?

Accepted Answer

A hot air balloon uses thermal energy to heat the air inside the balloon, causing it to rise and do work by lifting the balloon.

Question 4

Company X increases its profits every year by $50 million. Its growth in profits is

Accepted Answer

The profit increases by a constant amount each year, indicating a linear growth pattern.

Question 5

A particular automobile operates at an efficiency of 10%. Suppose that 20 gallons of gasoline are put into the auto's tank. Of this 20 gallons, how much will be "wasted" , i.e., how much will be consumed to produce exhaust heat and in other ways that do not actually get the car down the road?

Accepted Answer

The answer of A particular automobile operates at an efficiency...

Question 6

According to the second law of thermodynamics,

Accepted Answer

The second law of thermodynamics encompasses all these principles: energy processes involving thermal energy must have exhaust (A), thermal energy flows from hot to cold spontaneously (B), and the total entropy of a closed system cannot decrease (C).

Question 7

Country X increases its population by 5% per year. How long will it be before its population doubles?

Accepted Answer

The rule of 70 is a way to estimate the number of years it takes for a quantity to double, given a constant annual growth rate. By dividing 70 by the annual growth rate (5%), we get 14 years.

Question 8

During each cycle of its operation, a certain heat engine does 40 joules of work while exhausting 160 joules of thermal energy to the environment. The energy efficiency of this heat engine is

Accepted Answer

The answer of During each cycle of its operation, a...

Question 9

Company X increases its profits every year by 1% million. Its growth in profits is

Accepted Answer

The answer of Company X increases its profits every year...

Question 10

The "law of heat flow" is one form of

Accepted Answer

The "law of heat flow" is related to the second law of thermodynamics, which states that heat flows naturally from a hotter to a cooler body.

Question 11

Lilies in a certain pond double their total lake area covered every week. One day you notice that the pond is 1/8 covered with lilies. How long will it be before the pond is totally covered with lilies?

Accepted Answer

Since the lilies double their coverage every week, if the pond is 1/8 covered now, it will be 1/4 covered in one week, 1/2 covered in two weeks, and fully covered in three weeks.

Question 12

A large coal- fired electric generating plant burns about 1000 kg [one tonne] of coal every 10 seconds. About much of the tonne actually goes into producing electric energy?

Accepted Answer

The answer of A large coal- fired electric generating plant...

Question 13

Is a fuel- cell vehicle properly described as a "heat engine"?

Accepted Answer

A fuel-cell vehicle is not a heat engine because it converts chemical energy directly into electrical energy without involving thermal energy as an intermediary.

Question 14

"Hybrid drive" automobiles use

Accepted Answer

Hybrid drive automobiles typically use a small gasoline engine to drive an electric generator, which in turn powers electric motors that drive the wheels. This setup allows for improved fuel efficiency and reduced emissions compared to traditional gasoline-only vehicles.

Question 15

According to the second law of thermodynamics,

Accepted Answer

The second law of thermodynamics states that the total entropy of an isolated system can never decrease over time. It can remain constant in ideal cases where the system is in a reversible process, but in real processes, it always increases.

Question 16

The fuel that goes into a "hybrid drive" vehicle is

Accepted Answer

Hybrid drive vehicles use gasoline in combination with an electric motor to improve fuel efficiency.

Question 17

Compared with the efficiency of a typical steam- electric generating plant, the efficiency of a typical hydro- electric generating plant is

Accepted Answer

A hydro-electric plant is not a heat engine, so it does not suffer from the inefficiencies associated with the conversion of heat energy to work, as described by the second law of thermodynamics.

Question 18

Which of the following is one of the drawbacks of the automobile engine?

Accepted Answer

The internal combustion engine has multiple drawbacks, including low efficiency and the emission of pollutants like CO and CO2 into the atmosphere.

Question 19

Which of the following is the main reason for the fact that hydroelectric power plants are far more efficient than coal- fired electric power plants?

Accepted Answer

Hydroelectric plants convert potential energy directly into mechanical energy without the intermediate step of heat, thus avoiding the efficiency limitations imposed by the second law of thermodynamics on heat engines.

Question 20

A day during which the atmospheric temperature was 5°C would be described as

Accepted Answer

A temperature of 5°C is above freezing (0°C) but still considered cold, hence it is described as a cold day, but not freezing.

Quiz 7: Second Law of Thermodynamics: and You Cant Even Break Even

Large amounts of material can often be seen rising from the cooling towers often seen at steam- electric power plants. These emissions are mostly

Which of these uses thermal energy to do work?

Company X increases its profits every year by $50 million. Its growth in profits is

A particular automobile operates at an efficiency of 10%. Suppose that 20 gallons of gasoline are put into the auto's tank. Of this 20 gallons, how much will be "wasted" , i.e., how much will be consumed to produce exhaust heat and in other ways that do not actually get the car down the road?

According to the second law of thermodynamics,

Country X increases its population by 5% per year. How long will it be before its population doubles?

During each cycle of its operation, a certain heat engine does 40 joules of work while exhausting 160 joules of thermal energy to the environment. The energy efficiency of this heat engine is

Company X increases its profits every year by 1% million. Its growth in profits is

The "law of heat flow" is one form of

Lilies in a certain pond double their total lake area covered every week. One day you notice that the pond is 1/8 covered with lilies. How long will it be before the pond is totally covered with lilies?

A large coal- fired electric generating plant burns about 1000 kg [one tonne] of coal every 10 seconds. About much of the tonne actually goes into producing electric energy?

Is a fuel- cell vehicle properly described as a "heat engine"?

"Hybrid drive" automobiles use

According to the second law of thermodynamics,

The fuel that goes into a "hybrid drive" vehicle is

Compared with the efficiency of a typical steam- electric generating plant, the efficiency of a typical hydro- electric generating plant is

Which of the following is one of the drawbacks of the automobile engine?

Which of the following is the main reason for the fact that hydroelectric power plants are far more efficient than coal- fired electric power plants?

A day during which the atmospheric temperature was 5°C would be described as