Mark the letter A, B, C or D to indicate the correct answer to each of the following questions.

Question 17: _______ electric eels send a series of blips of electricity into the water around them and they can detect the pattern of electricity of the water changes.

A. Every

B. Of each

C. All

D. All of

_________electric eels send a series of blips of electricity into the water around them and they can detect the pattern of electricity of the water  changes.

A. Every

B. Of each

C. All

D. All of

Read the following passage and mark the letter A, B, C or D on your answer sheet to indicate the correct answer to each of the questions.

        Sunlight is solar energy. Sunlight is needed for growing plants that you eat to get energy. Sunlight is also used to make clean electricity. Burning fossil fuels to make electricity pollutes our atmosphere and rivers. Fossil fuels are expensive and limited sources of energy. Nuclear fission is used to create enormous amount of heat and electricity. However, nuclear fission forms dangerous radioactive waste.

          Sunlight offers many ways to get energy. A window can allow warm sunlight into your room. Solar water-heating systems can use sunlight to warm the water for your home, swimming pool and school. Sunlight also warms the Earth and causes wind. Electricity can be made by wind generators.

Photovoltaic, or PV system use a type of material that converts sunlight into electricity. PV systems can power your air conditioner or a satellite like the International Space Station. PV systems are also used to run a calculator, recharge cell phone, or even power lightweight cars.

          Sunlight is also changed into electricity by concentrating solar power or CSP systems. CSP systems have mirrors that focus the sunlight. The concentrated sunlight turns water into steam which turns a turbine that is connected to an electric generator. A CSP system usually uses sunlight to make steam. CSP power plants can store large amount of heat. The stored heat is used to make electricity at night. During cloud days, many CSP plants can also burn natural gas to provide the heat that is used to turn water into steam.

         Sunlight provides the energy needed to grow plants and make large amount of environmentally friendly heat and electricity. Solar energy can provide power today and for a long time in the future.

To help the readers understand some of the benefits of solar energy, the author ________

A. provides a list of solar energy projects.

B. lists in chronological order the invention of various systems that gather the energy of sunlight

C. describes in detail how a PV system works.

D. briefly compares and contrasts the differences in using fossil fuels, nuclear fission and solar energy in electric power systems

Read the following passage and mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to each of the questions from 36 to 42

The ability to conduct electricity is one of the key properties of a metal. Other solid materials such as silicon can conduct electricity but only effectively at certain temperatures. Also, some substances such as salt (sodium chloride) can conduct when molten or when dissolved in water. The ability of metals to conduct electricity is due to how their atoms bond together. In order to bond together the metal atoms lose at least one of their outermost electrons. This leaves the metal atoms with a positive charge and they are now strictly ions. The lost electrons are free to move in what is known as a sea of electrons. Since the electrons are negatively charged they attract the ions and this is what keeps the structure together.

 An electric current is a flow of charge and since the electrons in the sea of electrons are free to move they can be made to flow in one direction when a source of electrical energy such as a battery is connected to the metal. Hence we have an electric current flowing through the wire, and this is what makes metals such good conductors of electricity. The only other common solid conducting material that pencil users are likely to encounter is graphite (what the „lead’ of a pencil is made from). Graphite is a form of carbon and again the carbon atoms bond in such a way that there is a sea of electrons that can be made to flow as an electric current. Likewise, if we have an ionic substance like salt we can make the electrically charged ions flow to create a current but only when those ions are free to move, either when the substance is a liquid or dissolved in water. In its solid state an ionic substance like salt cannot conduct electricity as its charged ions cannot flow.

 Electrical insulators are substances that cannot conduct electricity well either, because they contain no charged particles or any charged particles they might contain do not flow easily. Water itself is a poor conductor of electricity as it does not contain a significant amount of fully charged particles (the ends of a water molecule are partly charged but overall the molecule is neutral). However, most water we encounter does contain dissolved charged particles, so it will be more conductive than pure water. Many of the problems that occur when touching electrical devices with wet hands result from the ever-present salt that is left on our skin through perspiration and it dissolves in the water to make it more conductive.

By Helena Gillespie and Rob Gillespie. Science for Primary School Teachers. OUP

According to the passage, a metal can conduct electricity due to ______.

A. the way its atoms bond together

B. the absence of free electrons

C. its atoms with a positive charge

D. the loss of one electron in the core of its atoms

Read the following passage and mark the letter A, B, C or D on your answer sheet to indicate the correct  answer to each of the following questions                               

The ability to conduct electricity is one of the key properties of  a metal. Other solid material such as silicon can conduct electricity but only effectively at certain temperatures. Also, some substances such as salt (sodium chloride) can conduct when molten or when dissolved  in water. The ability of metals to conduct electricity is due to how their atoms bond together. In order to bond together the metal atoms lose at least one of their outermost  electrons. This leaves the metal atoms with a positive charge and they are now strictly  ions. The lost electrons are free to move in what are known  as a sea of electrons. Since the electrons are negatively charged they attract the ions and this is what keeps the structure together.

            An electric current is a flow of charge and since the electrons in the sea of electrons are free to move they can be made to flow in one direction when a source of electrical energy such as a battery is connected to the metal. Hence we have an electric current flowing through the wire, and this is what makes metals such good conductors of electricity. The only other common solid conducting material that pencil users are likely to encounter is graphite (what the ‘lead’ of a pencil is made from). Graphite is a form of carbon and again the carbon atoms bond in such a way that there is a sea of electrons that can be made to flow as an electric current. Likewise, if we have an ionic substance like salt we can make the electrically charged ions flow to create a current but only when those ions are free to move, either when the substance is a liquid or dissolved in water. In its solid state an ionic substance like salt cannot conduct electricity as its charged ions cannot flow. Freshwater Aquarium Fish

Playlist Freshwater Aquarium Fish

       Electrical insulators are substances that cannot conduct electricity well either, because they contain no charged particles or any charged particles they might contain do not flow easily. Water itself is a poor conductor or electricity as it does not contain a significant amount of fully charged particles (the ends of a water molecule are partly charged but overall the molecule is neutral). However, most water we encounter does contain dissolved charged particles, so it will be more conductive than pure water. Many of the problems that occur when touching electrical devices with wet hands result from the ever-present salt that is left on our skin through perspiration and it dissolves in the water to make it more conductive.

By Helena Gillespie and Rob Gillespie. Science for Primary School Teacher. OUP

According to the passage, a metal can conduct electricity due to                    

A. the absence of free electrons

B. its atoms with a positive charge 

C. the way its atoms bond together 

D. the loss of one electron in the core of its atoms

Read the following passage and mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to each of the questions from 36 to 42

The ability to conduct electricity is one of the key properties of a metal. Other solid materials such as silicon can conduct electricity but only effectively at certain temperatures. Also, some substances such as salt (sodium chloride) can conduct when molten or when dissolved in water. The ability of metals to conduct electricity is due to how their atoms bond together. In order to bond together the metal atoms lose at least one of their outermost electrons. This leaves the metal atoms with a positive charge and they are now strictly ions. The lost electrons are free to move in what is known as a sea of electrons. Since the electrons are negatively charged they attract the ions and this is what keeps the structure together.

 An electric current is a flow of charge and since the electrons in the sea of electrons are free to move they can be made to flow in one direction when a source of electrical energy such as a battery is connected to the metal. Hence we have an electric current flowing through the wire, and this is what makes metals such good conductors of electricity. The only other common solid conducting material that pencil users are likely to encounter is graphite (what the „lead’ of a pencil is made from). Graphite is a form of carbon and again the carbon atoms bond in such a way that there is a sea of electrons that can be made to flow as an electric current. Likewise, if we have an ionic substance like salt we can make the electrically charged ions flow to create a current but only when those ions are free to move, either when the substance is a liquid or dissolved in water. In its solid state an ionic substance like salt cannot conduct electricity as its charged ions cannot flow.

 Electrical insulators are substances that cannot conduct electricity well either, because they contain no charged particles or any charged particles they might contain do not flow easily. Water itself is a poor conductor of electricity as it does not contain a significant amount of fully charged particles (the ends of a water molecule are partly charged but overall the molecule is neutral). However, most water we encounter does contain dissolved charged particles, so it will be more conductive than pure water. Many of the problems that occur when touching electrical devices with wet hands result from the ever-present salt that is left on our skin through perspiration and it dissolves in the water to make it more conductive.

By Helena Gillespie and Rob Gillespie. Science for Primary School Teachers. OUP

Which of the following could best serve as the title of the passage?

A. Electrical Insulators

B. Electrical Energy

C. Electrical Conductivity

D. Electrical Devices

Read the following passage and mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to each of the questions from 36 to 42

The ability to conduct electricity is one of the key properties of a metal. Other solid materials such as silicon can conduct electricity but only effectively at certain temperatures. Also, some substances such as salt (sodium chloride) can conduct when molten or when dissolved in water. The ability of metals to conduct electricity is due to how their atoms bond together. In order to bond together the metal atoms lose at least one of their outermost electrons. This leaves the metal atoms with a positive charge and they are now strictly ions. The lost electrons are free to move in what is known as a sea of electrons. Since the electrons are negatively charged they attract the ions and this is what keeps the structure together.

 An electric current is a flow of charge and since the electrons in the sea of electrons are free to move they can be made to flow in one direction when a source of electrical energy such as a battery is connected to the metal. Hence we have an electric current flowing through the wire, and this is what makes metals such good conductors of electricity. The only other common solid conducting material that pencil users are likely to encounter is graphite (what the „lead’ of a pencil is made from). Graphite is a form of carbon and again the carbon atoms bond in such a way that there is a sea of electrons that can be made to flow as an electric current. Likewise, if we have an ionic substance like salt we can make the electrically charged ions flow to create a current but only when those ions are free to move, either when the substance is a liquid or dissolved in water. In its solid state an ionic substance like salt cannot conduct electricity as its charged ions cannot flow.

 Electrical insulators are substances that cannot conduct electricity well either, because they contain no charged particles or any charged particles they might contain do not flow easily. Water itself is a poor conductor of electricity as it does not contain a significant amount of fully charged particles (the ends of a water molecule are partly charged but overall the molecule is neutral). However, most water we encounter does contain dissolved charged particles, so it will be more conductive than pure water. Many of the problems that occur when touching electrical devices with wet hands result from the ever-present salt that is left on our skin through perspiration and it dissolves in the water to make it more conductive.

By Helena Gillespie and Rob Gillespie. Science for Primary School Teachers. OUP

Salt in its solid state is not able to conduct electricity because ______.

A. . its charged ions can flow easily

B. it cannot create any charged ions

C. it has free electrons

D. its charged ions are not free to move

Read the following passage and mark the letter A, B, C or D on your answer sheet to indicate the correct answer to each of the questions.

        Sunlight is solar energy. Sunlight is needed for growing plants that you eat to get energy. Sunlight is also used to make clean electricity. Burning fossil fuels to make electricity pollutes our atmosphere and rivers. Fossil fuels are expensive and limited sources of energy. Nuclear fission is used to create enormous amount of heat and electricity. However, nuclear fission forms dangerous radioactive waste.

          Sunlight offers many ways to get energy. A window can allow warm sunlight into your room. Solar water-heating systems can use sunlight to warm the water for your home, swimming pool and school. Sunlight also warms the Earth and causes wind. Electricity can be made by wind generators.

Photovoltaic, or PV system use a type of material that converts sunlight into electricity. PV systems can power your air conditioner or a satellite like the International Space Station. PV systems are also used to run a calculator, recharge cell phone, or even power lightweight cars.

          Sunlight is also changed into electricity by concentrating solar power or CSP systems. CSP systems have mirrors that focus the sunlight. The concentrated sunlight turns water into steam which turns a turbine that is connected to an electric generator. A CSP system usually uses sunlight to make steam. CSP power plants can store large amount of heat. The stored heat is used to make electricity at night. During cloud days, many CSP plants can also burn natural gas to provide the heat that is used to turn water into steam.

         Sunlight provides the energy needed to grow plants and make large amount of environmentally friendly heat and electricity. Solar energy can provide power today and for a long time in the future.

Which of the following statements is NOT true?

A. Fossil fuel supplies are unlimited.

B. Solar energy is the energy that comes from the sun.

C. PV systems provide electricity for the International Space Station

D. A CSP power plant can produce steam even at night.