Electrical Principles And Technology Unit Review

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  • 1/45 Questions

    The measurement used to measure voltage is ________.

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About This Quiz

A unt review for this unit including: Calculating Power, Watts, Resistance, Current, Efficiency etc., Static Electricity, Electrical Safety, Current Electricity, Cells & Batteries, Electrical Circuits (ie. Flashlight), Resistance, Energy Transformation/ Forms, Motors (ie. St Louis Motor, Magnetism) and Electricity Generators.
Good Luck :)

Electrical Principles And Technology Unit Review - Quiz

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  • 2. 

    What is power measured in?

    Explanation
    Power is measured in watts (W). Watts is the standard unit used to quantify the rate at which work is done or energy is transferred. It represents the amount of energy consumed or produced per unit of time. The lowercase "watts" and the abbreviation "W" both refer to the same unit of measurement.

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  • 3. 

    These types of conductors have no resistance to electron flow, which is why they are known to be perfect conductors. They are called _______.

    • Superconductors

    • Metallic conductors

    • Resistance-less conductors

    • Magnetic conductors

    Correct Answer
    A. Superconductors
    Explanation
    Superconductors are conductors that have zero electrical resistance, allowing electrons to flow through them without any hindrance. This unique property makes them perfect conductors. Unlike metallic conductors, which still have some resistance, superconductors exhibit no resistance at all. The term "resistance-less conductors" accurately describes superconductors as they lack any resistance to electron flow. Magnetic conductors, on the other hand, refer to materials that can conduct or interact with magnetic fields, but this term does not capture the zero resistance characteristic of superconductors.

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  • 4. 

    The measurement used to measure current is _______.

    Correct Answer
    Amps
    amps
    amperes
    Amperes
    A
    Explanation
    The measurement used to measure current is amps or amperes. The symbol for ampere is A.

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  • 5. 

    Why do objects attract to one another?

    • Opposite charges

    • Similar charges

    • Neutrons

    • Electrons

    Correct Answer
    A. Opposite charges
    Explanation
    Objects attract to one another due to opposite charges. Opposite charges create an electric field around them, and when two objects with opposite charges come close to each other, they experience a force of attraction. This force is known as the electrostatic force and is responsible for objects sticking together or attracting to each other.

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  • 6. 

    An example of a static electrical charge is _______. 

    • Lightning

    • Batteries

    • Current

    • Ohms

    Correct Answer
    A. Lightning
    Explanation
    An example of a static electrical charge is lightning. Lightning is a natural phenomenon that occurs when there is a buildup of static electricity in the atmosphere. It is a sudden discharge of electrical energy that can occur between clouds, from a cloud to the ground, or between different parts of the same cloud. This discharge creates a bright flash of light and a loud thunderclap. Unlike other options like batteries, current, or ohms, which are related to electrical energy in different ways, lightning specifically represents a static electrical charge due to its sudden and powerful nature.

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  • 7. 

    A toaster is an example of this energy transformation:

    • Electrical to thermal

    • Thermal to electrical

    • Electrical to mechanical

    • Chemical to thermal

    Correct Answer
    A. Electrical to thermal
    Explanation
    A toaster is an example of electrical to thermal energy transformation because it converts electrical energy into heat energy to toast bread.

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  • 8. 

    How much current is created when a 30 V battery creates a current through a 15 Ω resistor?

    Correct Answer
    2 A
    2A
    2 amperes
    2 amps
    2 Amperes
    2 Amps
    Explanation
    The current created when a 30 V battery creates a current through a 15 Ω resistor is 2 A (amperes) or 2 Amps. This can be determined using Ohm's Law, which states that the current (I) flowing through a conductor is equal to the voltage (V) across the conductor divided by the resistance (R) of the conductor. In this case, the voltage is 30 V and the resistance is 15 Ω, therefore the current is 30 V / 15 Ω = 2 A.

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  • 9. 

    What is an disadvantage of stringing lamps in a series circuit?

    • If one lamp goes out, they all burn out as well

    • Requires more energy

    • Has more resistance

    • Has less current

    Correct Answer
    A. If one lamp goes out, they all burn out as well
    Explanation
    In a series circuit, the lamps are connected in a chain, so the same current flows through each lamp. If one lamp goes out, it breaks the circuit and interrupts the flow of current, causing all the lamps to go out. This is a disadvantage because it means that the failure of one lamp can result in the failure of all the lamps in the circuit.

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  • 10. 

    When electrons discharge, they go into the ground via a _________ wire.

    Correct Answer
    Ground
    ground
    Explanation
    When electrons discharge, they go into the ground via a ground wire. The ground wire provides a path of least resistance for the electrons to flow into the ground, preventing any build-up of excess electrical charge. This helps to protect electrical equipment and prevent electrical shocks or damage. The term "ground" refers to the Earth, which serves as a large reservoir of charge that can absorb and dissipate the excess electrons.

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  • 11. 

    A DC generator is a device that converts mechanical energy into electrical energy using current which  ________.

    • Flows in one direction

    • Changes direction

    • Has lots of electrons

    • Uses a lot of voltage

    Correct Answer
    A. Flows in one direction
    Explanation
    A DC generator is designed to convert mechanical energy into electrical energy by producing a current that flows in one direction. This is achieved through the use of a commutator, which ensures that the current generated by the generator always flows in the same direction. By maintaining a constant flow of current in one direction, the DC generator is able to produce a steady and consistent output of electrical energy.

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  • 12. 

    A __________ is a device that converts thermal energy into electrical energy. Consisting of two different metals joined together to conduct heat. 

    • Thermocouple

    • Motor

    • Transformer

    • Solar panel

    Correct Answer
    A. Thermocouple
    Explanation
    A thermocouple is a device that converts thermal energy into electrical energy. It is made up of two different metals that are joined together to conduct heat. When there is a temperature difference between the two junctions of the thermocouple, it creates a voltage difference, which can be used to generate electricity. This process is known as the Seebeck effect. Therefore, a thermocouple is the correct answer for a device that converts thermal energy into electrical energy.

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  • 13. 

    A _________ is a continuos resistor used to regulate electric current, it is also used to change the current flow.

    • Rheostat

    • Voltmeter

    • Ammeter

    • Battery

    Correct Answer
    A. Rheostat
    Explanation
    A rheostat is a type of resistor that is used to regulate electric current. It is also used to change the current flow. Unlike other options such as voltmeter, ammeter, and battery, a rheostat specifically serves the purpose of controlling and adjusting the flow of electric current.

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  • 14. 

    An ordinary light bulb: 100 J of energy comes into a light bulb 5 J are used for light 95 J are released as heat What is the efficency of the light bulb? 

    Correct Answer
    5 %
    5%
    5 percent
    5 Percent
    five percent
    Five percent
    Five Percent
    Explanation
    The efficiency of the light bulb is 5%. This means that out of the 100 J of energy that comes into the light bulb, only 5 J are used for light, while the remaining 95 J are released as heat. The efficiency is calculated by dividing the useful output energy (5 J) by the total input energy (100 J) and multiplying by 100 to get a percentage. In this case, (5 J / 100 J) * 100 = 5%.

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  • 15. 

    What is an advantage of stringing lamps in a parallel circuit?

    • One lamp failure will not affect the other lamps

    • Requires less energy

    • Has less resistance

    • Has more voltage

    Correct Answer
    A. One lamp failure will not affect the other lamps
    Explanation
    When lamps are strung in a parallel circuit, each lamp has its own separate pathway for the flow of electric current. This means that if one lamp fails, the other lamps will still receive the necessary current to continue functioning. Therefore, one lamp failure will not affect the other lamps in a parallel circuit.

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  • 16. 

    The process of __________ is when you coat a surface of a conducting material with metal.

    • Electroplating

    • Electrolysis

    • Potential difference

    • Metal coating

    Correct Answer
    A. Electroplating
    Explanation
    Electroplating is the process of coating a surface of a conducting material with metal. It involves the use of an electric current to deposit a thin layer of metal onto the surface of an object. This process is commonly used to enhance the appearance of objects, provide corrosion resistance, improve conductivity, and increase durability. Electrolysis refers to the decomposition of a compound using an electric current, potential difference is the voltage between two points in an electric circuit, and metal coating is a general term that can refer to various methods of applying a layer of metal onto a surface.

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  • 17. 

    A AC generator is a device that converts mechanical energy into electrical energy using current which  ________.

    • Flows in one direction

    • Changes direction

    • Has lots of electrons

    • Uses a lot of voltage

    Correct Answer
    A. Changes direction
    Explanation
    An AC generator is a device that converts mechanical energy into electrical energy by producing an alternating current. The alternating current periodically changes its direction, flowing first in one direction and then in the opposite direction. This alternating current is essential for the efficient transmission of electrical energy over long distances and for powering various electrical devices.

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  • 18. 

    You can make a ________ by winding current-carrying wire into a coil around a iron core.

    • Electromagnet

    • Motor

    • Circuit

    • Ground wire

    Correct Answer
    A. Electromagnet
    Explanation
    An electromagnet can be made by winding a current-carrying wire into a coil around an iron core. When an electric current flows through the wire, it creates a magnetic field around the coil. The iron core enhances the strength of the magnetic field. This electromagnet can be used in various applications such as lifting heavy objects, generating power in electric motors, and controlling switches in circuits.

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  • 19. 

    Which of the following energy sources used in generating power is considered a fossil fuel?

    • Water

    • Biomass

    • Natural gas

    • Uranium

    Correct Answer
    A. Natural gas
    Explanation
    Natural gas is considered a fossil fuel because it is formed from the remains of ancient plants and animals that were buried and subjected to high heat and pressure over millions of years. It is primarily composed of methane, a greenhouse gas, and is extracted from underground reservoirs. Natural gas is commonly used in power generation due to its high energy content and relatively low carbon emissions compared to other fossil fuels like coal and oil.

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  • 20. 

    A ________ is designed to interrupt the power to a circuit when the current flow exceeds safe levels.

    Correct Answer
    fuse
    Fuse
    Explanation
    A fuse is a safety device that is designed to interrupt the power to a circuit when the current flow exceeds safe levels. When the current exceeds the rated value of the fuse, it causes the fuse to melt and break the circuit, preventing any further flow of electricity. This helps to protect the circuit and the connected devices from damage or overheating caused by excessive current flow.

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  • 21. 

    The longer the wire is, the ______ its resistance.

    • Lower

    • Greater

    • Wider

    • Thinner

    Correct Answer
    A. Greater
    Explanation
    The longer the wire is, the greater its resistance. This is because resistance is directly proportional to the length of the wire. As the wire becomes longer, there is an increase in the number of atoms or ions that the electrons have to pass through, resulting in more collisions and hindrance to the flow of current. Therefore, the resistance of the wire increases.

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  • 22. 

    Determine if this statment true or false: A generator stores energy.

    • True

    • False

    Correct Answer
    A. False
    Explanation
    A generator does not store energy. Instead, it converts mechanical energy into electrical energy. It uses a fuel source, such as gasoline or diesel, to power an engine that rotates a magnet within a coil of wire, producing an electrical current. However, the generator itself does not have the capability to store energy for later use.

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  • 23. 

    A _________ occurs when there is a low resistance connection between two conductors supplying electrical power to any circuit.

    • Short circuit

    • Malfunction

    • Electrical shock

    • Spark

    Correct Answer
    A. Short circuit
    Explanation
    A short circuit occurs when there is a low resistance connection between two conductors supplying electrical power to any circuit. This connection bypasses the normal load, causing a sudden surge of current. This can lead to overheating, damage to the circuit, and potentially a fire hazard.

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  • 24. 

    The process of which you use a small battery to split molecules into their elements is called _________.

    • Electrolysis

    • Hydro-plating

    • Hydrolysis

    • Energy transformation

    Correct Answer
    A. Electrolysis
    Explanation
    Electrolysis is the process in which a small battery is used to split molecules into their elements. This process involves the use of an electric current to drive a non-spontaneous chemical reaction, causing the decomposition of compounds into their constituent elements. Hydro-plating and hydrolysis are not related to the splitting of molecules using a small battery, while energy transformation is a broader concept that does not specifically refer to this particular process.

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  • 25. 

    The thicker the wire is, the ________ its resistance.

    • Lower

    • Greater

    Correct Answer
    A. Lower
    Explanation
    The thicker the wire is, the lower its resistance. This is because a thicker wire provides more space for the flow of electrons, reducing the chances of collisions between the electrons and the wire's atoms. As a result, the resistance to the flow of electric current decreases, leading to a lower resistance value.

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  • 26. 

    What is an advantage of stringing lamps in a series circuit?

    • Requires less energy

    • Requires more energy

    • Less resistance

    • Greater resistance

    Correct Answer
    A. Requires less energy
    Explanation
    Stringing lamps in a series circuit requires less energy because in a series circuit, the current is the same through each component. Therefore, when lamps are connected in series, the total voltage is divided equally among them. This means that each lamp receives a lower voltage compared to when it is connected individually. Since the power consumed by a device is directly proportional to the voltage applied to it, stringing lamps in a series circuit reduces the energy consumption of each lamp.

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  • 27. 

    The _____ (one or two words) in an electric motor attracts the armature to create motion; in which, creates electricity.

    Correct Answer
    Permanent magnets
    permanent magnets
    Permanent Magnets
    magnet
    Magnet
    permanent magnet
    Permanent magnet
    magnets
    Magnets
    Explanation
    The correct answer is "permanent magnets". In an electric motor, the permanent magnets attract the armature, which creates motion. This motion then generates electricity.

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  • 28. 

    Who had made the first practical battery by piling copper and zinc disks on top of each other, and then seperating them with electrolyte-soaked paper discs. 

    • Alessandro Volta

    • Faraday

    • Van de Graff

    • Ohm

    Correct Answer
    A. Alessandro Volta
    Explanation
    Alessandro Volta is credited with making the first practical battery by piling copper and zinc disks on top of each other and separating them with electrolyte-soaked paper discs. His invention, known as the Voltaic Pile, was an early form of battery that produced a continuous flow of electricity. Volta's groundbreaking work laid the foundation for the development of modern batteries and greatly contributed to the field of electrochemistry.

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  • 29. 

    The ______  a wire is, the lower the resistance.

    • Cooler

    • Hotter

    • Less conductive

    Correct Answer
    A. Cooler
    Explanation
    The lower the temperature of a wire, the lower its resistance. This is because at lower temperatures, the atoms in the wire vibrate less, causing less obstruction to the flow of electrons. As a result, the electrons can move more freely through the wire, leading to lower resistance. Conversely, at higher temperatures, the atoms vibrate more vigorously, creating more obstacles for the electrons and increasing resistance. Therefore, the correct answer is "cooler".

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  • 30. 

    How does spraying water on laundry help reduce static cling?

    • The water absorbs electrical charge

    • The water contains protons

    • Water is a magnet

    • The charges leave onto a different object with opposite charges

    Correct Answer
    A. The water absorbs electrical charge
    Explanation
    Water is a polar molecule, meaning it has a positive and a negative end. When water is sprayed on laundry, it can absorb electrical charge because the positive and negative ends of the water molecules attract and neutralize the static charge present on the laundry. This helps to reduce static cling as the charges are no longer present to cause the clothes to stick together.

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  • 31. 

    A _________, is a paste or liquid that conducts electricity because it contains chemicals that form ions.

    • Electrolyte

    • Battery

    • Dry cell

    • Wet cell

    Correct Answer
    A. Electrolyte
    Explanation
    An electrolyte is a substance, either in paste or liquid form, that can conduct electricity due to the presence of chemicals that form ions. These ions are responsible for carrying the electric charge through the solution. In the context of the given question, an electrolyte is the correct answer as it accurately describes the substance that conducts electricity in a battery or cell.

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  • 32. 

    A hair dryer has a power rating of 1000 W. It is plugged into a 120V outlet. What is the current flowing through the hair dryer? (Round to the nearest tenth)

    Correct Answer
    8.3 A
    8.3A
    Explanation
    The current flowing through the hair dryer can be calculated using Ohm's Law, which states that current (I) is equal to power (P) divided by voltage (V). In this case, the power rating of the hair dryer is 1000 W and the voltage is 120V. Therefore, the current flowing through the hair dryer is 1000/120 = 8.3 A.

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  • 33. 

    The movement of charges from an object to another without further movement is called __________.

    Correct Answer
    Static Electricity
    Static electricity
    static electricity
    Explanation
    The movement of charges from one object to another without further movement is known as static electricity. This phenomenon occurs when there is an imbalance of positive and negative charges on objects, causing them to attract or repel each other. Static electricity is commonly experienced through activities such as rubbing two objects together or walking on a carpet and then touching a metal object, resulting in a small electric shock.

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  • 34. 

    A 850 W oven requires a 7A current. What is the voltage (round to nearest tenth)?

    Correct Answer
    121.4 V
    121.4 volts
    121.4V
    121.4 Volts
    Explanation
    The voltage can be calculated using the formula P = IV, where P is the power in watts, I is the current in amperes, and V is the voltage in volts. Rearranging the formula to solve for V, we have V = P/I. Plugging in the values, we get V = 850 W / 7 A = 121.4 V. Therefore, the voltage is 121.4 V.

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  • 35. 

    _______ is the direction of a magnetic or electric field.

    Correct Answer
    Polarity
    polarity
    Explanation
    The term "polarity" refers to the direction of a magnetic or electric field. It is used to describe the orientation or alignment of the field lines, indicating the positive and negative ends or poles. In the context of magnets, polarity determines how the north and south poles are arranged. In the case of electric fields, polarity indicates the direction of the flow of electric charge.

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  • 36. 

    A dry cell is different from a wet cell because it is ____________.

    • Rechargeable

    • Non-rechargeable

    • Wet

    • Less resistance

    Correct Answer
    A. Non-rechargeable
    Explanation
    A dry cell is different from a wet cell because it is non-rechargeable. Unlike a wet cell, which can be recharged by replenishing the electrolyte, a dry cell cannot be recharged. It contains a paste or gel electrolyte, which makes it more portable and less prone to leakage. Dry cells are commonly used in household batteries, such as AA or AAA batteries, while wet cells are typically found in car batteries or larger industrial applications.

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  • 37. 

    What is an disadvantage of stringing lamps in a parallel circuit?

    • Requires more energy

    • Has more resistance

    • One lamp burns out they all do as well

    • Lights become dimmer when lamps are added

    Correct Answer
    A. Requires more energy
    Explanation
    Stringing lamps in a parallel circuit does not require more energy. In fact, it is the opposite. In a parallel circuit, each lamp receives the same voltage, so the total energy consumed by the lamps is divided among them. This means that each lamp will receive the same amount of energy regardless of the number of lamps in the circuit. Therefore, the statement that stringing lamps in a parallel circuit requires more energy is incorrect.

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  • 38. 

    ____________ is the energy carried by charged particles.

    Correct Answer
    Electrical energy
    Electrical Energy
    electrical energy
    Explanation
    The correct answer is electrical energy. Electrical energy refers to the energy that is carried by charged particles, such as electrons. It is the energy associated with the movement of these charged particles through a conductor, such as a wire, and is commonly used to power electrical devices and systems. The term "electrical energy" can be written in various forms, including capitalized or lowercase letters, but the meaning remains the same.

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  • 39. 

    Find the cost to use this appliance per month (assume 30 days), using the info below: kWh= $0.07 Toaster:  0.2 hours per day Power rating of 1000 W = $?  (round to nearest hundreth place, just as real money)

    Correct Answer
    0.42
    $0.42
    Explanation
    The cost to use the toaster per month can be calculated by multiplying the power rating of the toaster (1000 W) by the number of hours per day it is used (0.2 hours), then multiplying that by the cost per kilowatt-hour ($0.07), and finally multiplying by the number of days in a month (30).

    So, the calculation would be: (1000 W * 0.2 hours * $0.07/kWh * 30 days) = $0.42. Therefore, the cost to use the toaster per month is $0.42.

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  • 40. 

    Calculate the efficiency of an 1000 W kettle that takes 4 minutes to boil water. To heat the water to boiling point, it takes 196,000 J of energy. What is the efficiency of the kettle (round to nearest ones place ie. 12.4%= 12%)?

    Correct Answer
    82 %
    82%
    82 percent
    82 Percent
    Eighty two percent
    eighty two percent
    Explanation
    Here are the calculations to figuring out the efficiency of the kettle:

    E1 = Power x Time
    E= 196, 000 J

    E2= Power x Time
    E= (1000 W) x (4 min= 240 seconds)
    E= (1000 W) x (240 sec.)

    E= 240, 000 J

    Percent Efficiency= Joules of useful energy / joules of input energy

    Efficiency= 196000/ 240000
    E= 0.82
    E= 0.82 x 100
    E= 82%

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  • 41. 

    What is the total resistance of a parallel circuit with two 20-ohm resistors and a 10-ohm resistor?

    Correct Answer
    5
    5 Ohms
    5 ohms
    five
    five ohms
    Five ohms
    Five Ohms
    Explanation
    The total resistance of a parallel circuit is calculated using the formula 1/Rt = 1/R1 + 1/R2 + 1/R3 + ... In this case, the two 20-ohm resistors and the 10-ohm resistor are connected in parallel, so the formula becomes 1/Rt = 1/20 + 1/20 + 1/10. Simplifying this equation gives 1/Rt = 1/20 + 1/20 + 2/20, which further simplifies to 1/Rt = 4/20. Inverting both sides of the equation gives Rt = 20/4, which equals 5 ohms.

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  • 42. 

    A microwave has a power rating of 800 W. If you cook a roast chicken in the microwave for 30 minutes on high, how many jules of energy are converted into heat by the microwave?

    Correct Answer
    1440000 J
    1440000 J
    1.4 MJ
    1 440 000 J
    Explanation
    The power rating of the microwave is given as 800 W. Power is defined as the rate at which energy is transferred or converted. Since the microwave operates for 30 minutes, we need to calculate the total energy converted. Using the formula: Energy = Power x Time, we can calculate the energy as 800 W x 30 minutes = 24,000 W-minutes. Since 1 J = 1 W-min, we can convert the energy to joules by multiplying by 60 (to convert minutes to seconds) to get 1,440,000 J. Therefore, the correct answer is 1440000 J. The other options are just different representations of the same value.

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  • 43. 

    Nuclear waste is disposed of by...

    • Mixing with chemicals

    • Diluting with water

    • Burying underground

    • Sending it off into space

    Correct Answer
    A. Diluting with water
    Explanation
    Nuclear waste is disposed of by diluting with water to reduce its concentration and make it less harmful. This process is known as dilution. By mixing the waste with a large volume of water, the radioactive materials are spread out and their impact is minimized. This method is commonly used for liquid radioactive waste. However, it is important to note that dilution is not a permanent solution and further steps are required for long-term storage or disposal of nuclear waste.

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  • 44. 

    The more charged particles in a solution _________.

    • The more voltage it produces

    • The more resistance there is

    • The less resistance there is

    • The less voltage is produced

    Correct Answer
    A. The less resistance there is
    Explanation
    When there are more charged particles in a solution, it means that there are more ions available to carry electric current. This leads to a decrease in resistance, as the ions can move more easily through the solution. As a result, the solution will have less resistance, allowing for a greater flow of electric current.

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  • Mar 20, 2023
    Quiz Edited by
    ProProfs Editorial Team
  • Jun 12, 2012
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    Smartiecheez
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