Electricity and Electric Circuits
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Questions and Answers

What is the relationship between voltage rise and voltage drop in a series circuit?

  • Voltage rise is greater than the total of each voltage drop.
  • Voltage drop is equal to zero.
  • Voltage rise equals the total of each voltage drop. (correct)
  • Voltage rise does not affect the voltage drop.

In a parallel circuit, what must be true for the components connected in parallel?

  • They all have the same current flowing through them.
  • Each component operates independently. (correct)
  • The total resistance is equal to the sum of individual resistances.
  • The total voltage across each component is different.

How does the addition of more branches in a parallel circuit affect the total resistance?

  • It has no impact on the resistance.
  • It increases the total resistance.
  • It decreases the total resistance. (correct)
  • It keeps the total resistance constant.

What is the total current in a parallel circuit compared to the currents in its branches?

<p>It equals the sum of the currents in its parallel branches. (A)</p> Signup and view all the answers

What happens to the voltage across components in a series circuit?

<p>It is divided among the components. (C)</p> Signup and view all the answers

What defines the electric current in a wire?

<p>The net amount of charge passing through a cross section per unit time (B)</p> Signup and view all the answers

What is the unit of measurement for electric current?

<p>Ampere (C)</p> Signup and view all the answers

Which of the following statements about direct current (DC) is true?

<p>It involves charges moving in the same direction continuously (D)</p> Signup and view all the answers

What happens to electric current if there is no electric potential between two points?

<p>The current is not present (D)</p> Signup and view all the answers

How is current calculated?

<p>Current is charge over time (C)</p> Signup and view all the answers

Which one of the following electrical sources typically provides alternating current (AC)?

<p>Household electrical outlets (A)</p> Signup and view all the answers

What device is used to measure electric current?

<p>Ammeter (B)</p> Signup and view all the answers

What defines alternating current (AC)?

<p>The charges switch direction regularly (D)</p> Signup and view all the answers

What is the primary unit used to measure electric power?

<p>Watt (W) (A)</p> Signup and view all the answers

Which statement correctly describes a Direct Current (DC) circuit?

<p>The current flows uni-directionally. (D)</p> Signup and view all the answers

What does the formula P = IV represent?

<p>The power consumed by an electric appliance. (C)</p> Signup and view all the answers

What is the main component of a Direct Current (DC) circuit?

<p>Resistor (A)</p> Signup and view all the answers

Which of the following best describes an electric circuit?

<p>Any path along which current and electrons can flow. (B)</p> Signup and view all the answers

What does the electromotive force (EMF) do in a battery?

<p>It maintains the maximum potential difference across terminals. (B)</p> Signup and view all the answers

Why is a resistor critical in a DC circuit?

<p>It controls the flow of electric current. (A)</p> Signup and view all the answers

What determines the cost of electrical energy usage measured in kilowatt-hours (kWh)?

<p>The length of time an appliance is used. (C)</p> Signup and view all the answers

What is defined as the electric potential produced by an electrochemical cell or a changing magnetic field?

<p>Electromotive Force (EMF) (B)</p> Signup and view all the answers

What is the primary function of a battery in an electric circuit?

<p>To convert chemical energy into electrical energy (D)</p> Signup and view all the answers

What is the potential difference across a small battery typically?

<p>1.5 volts (A)</p> Signup and view all the answers

How does voltage difference relate to electric potential?

<p>Voltage is defined as the work done per unit charge. (B)</p> Signup and view all the answers

What do batteries do to the charges within them?

<p>They raise the charges to a higher potential. (C)</p> Signup and view all the answers

What is the relationship between EMF and voltage?

<p>Voltage exists between two points, while EMF is associated with a source. (D)</p> Signup and view all the answers

Which feature distinguishes an insulator from a conductor?

<p>Insulators do not permit electric current to pass through. (A)</p> Signup and view all the answers

When moving a test charge within a static electric field, what is required?

<p>Work done against the field (A)</p> Signup and view all the answers

What occurs during the grounding of a negatively charged electroscope?

<p>Electrons flow from the electroscope to the ground. (B)</p> Signup and view all the answers

How does the grounding of a positively charged electroscope occur?

<p>Electrons flow from the ground to the electroscope. (D)</p> Signup and view all the answers

Which factor influences the physiological effects of electric current on the body?

<p>The resistance of one’s body. (D)</p> Signup and view all the answers

What is a mild effect of electric current on the human body at 0.001 A?

<p>Mild tingling sensation. (D)</p> Signup and view all the answers

At what current level can muscle spasms occur?

<p>0.01-0.02 A (C)</p> Signup and view all the answers

What is the current threshold that may cause fatal heart fibrillation?

<p>0.2 A (B)</p> Signup and view all the answers

Which is a reason for grounding to the earth?

<p>To pass through electric current. (B)</p> Signup and view all the answers

What condition can affect a person's body resistance with regards to electric current?

<p>Skin moisture condition: wet/dry. (C)</p> Signup and view all the answers

What is the SI unit of power?

<p>Watt (W) (D)</p> Signup and view all the answers

How much power is equivalent to 1 horsepower?

<p>746 watts (D)</p> Signup and view all the answers

What happens to power if the time taken to do a certain amount of work is decreased?

<p>Power increases (D)</p> Signup and view all the answers

Which statement about work is correct?

<p>Work has nothing to do with the time the force acts. (A)</p> Signup and view all the answers

If a person takes longer to go up and down the stairs, what can be inferred about the power exerted?

<p>The power exerted is lower. (C)</p> Signup and view all the answers

Which of the following units is not a measure of power?

<p>Joule (J) (A)</p> Signup and view all the answers

What does power quantify in a physical context?

<p>The rate at which energy is transferred (D)</p> Signup and view all the answers

How is the relationship between power and time best described?

<p>Power is inversely proportional to time. (B)</p> Signup and view all the answers

Flashcards

Voltage across a battery

The potential difference between the terminals of a battery, ranging from 1.5V to 12V.

Insulator

A material that does not allow electric current to flow.

EMF (Electromotive Force)

The electric potential produced by an electrochemical cell or changing a magnetic field.

Potential Difference

The difference in electric potential energy per unit charge between two points.

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Voltage

The difference in electric potential between two points.

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Electrochemical cell

A device that converts chemical energy into electrical energy.

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Potential Energy (of Charge)

The energy possessed by a charge due to its position in an electric field.

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Electric Potential

The electric potential energy per unit charge at a specific point in space.

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Electric Current

The flow of charged particles (e.g., electrons) in a wire or circuit.

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Electric Current Measurement

Measured in Amperes (A). 1 Ampere = 1 Coulomb of charge per second.

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Direct Current (DC)

Charges moving in the same direction continuously.

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Alternating Current (AC)

Charges move back and forth in a circuit

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Ammeter

Device used to measure electric current.

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Current Prerequisite

An Electric Current requires a potential difference between two points

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Current Definition (Precise)

Net amount of charge passing through a wire's full cross section per unit time.

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Current in Metals

Movement of electrons causes the current

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Kilowatt-hour (kWh)

A unit of electrical energy.

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Electric Power (P)

The rate at which electric energy is converted.

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SI unit for Electric Power

Watt (W)

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DC Circuit

Closed path in a circuit where DC flows.

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Electric Circuit

A complete path for current flow.

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Electromotive Force (EMF)

The maximum potential difference across a battery's terminals.

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Electric Circuit Components

Energy source, consuming device, & connecting wires.

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Series Circuit

A circuit where all components are connected in a single loop, allowing current to flow through each component sequentially.

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Parallel Circuit

A circuit where components are connected on separate branches, allowing current to flow through different paths simultaneously.

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Voltage Rise

The increase in electric potential provided by a power source, usually a battery.

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Voltage Drop

The decrease in electric potential across a resistor or other load as energy is consumed.

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Total Resistance in Series Circuit

The sum of the individual resistances of each component in the series circuit.

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Power (SI unit)

The rate at which energy is transferred or work is done, measured in Watts (W).

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Horsepower (hp)

A unit of power, equivalent to 746 Watts or 0.746 kilowatts. Commonly used to describe engine power.

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Work (in relation to power)

Work done does not depend on the time it takes, only on the force applied and the displacement caused.

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Power & Time

Power is inversely proportional to time. The shorter the time taken to do the same work, the higher the power.

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Example of Work (no time dependence)

A person going up and down the stairs performs the same amount of work regardless of how fast they move.

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Grounding

Connecting a charged object to the earth to neutralize its charge by transferring electrons.

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Grounding a negatively charged electroscope

Electrons flow from the negatively charged electroscope to the ground, neutralizing it.

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Grounding a positively charged electroscope

Electrons flow from the ground to the positively charged electroscope, neutralizing it.

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Physiological Effects of Electric Current

The effects of an electric current flowing through the body, ranging from tingling to muscle spasms to death.

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Body Resistance

A measure of how easily electric current flows through the body, influenced by factors like moisture.

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Mild Tingling Sensation

A sensation caused by a low electric current of about 0.001 A.

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Muscle Spasms

Involuntary muscle contractions caused by an electric current of about 0.01 to 0.02 A.

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Fatal Electric Current

An electric current of about 0.2 A that can cause heart fibrillation, leading to death.

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Study Notes

Electricity

  • Electricity is the presence and flow of electric charges.
  • Electric charge is inherent in matter, carried by elementary particles.
  • Two types of charge: positive and negative.
  • The fundamental unit of charge is the Coulomb (C).
  • Each charge has an absolute value of 1.6 x 10⁻¹⁹ Coulombs.
  • Conductors allow electric current to flow through them.
    • Examples: copper, aluminum, steel.
  • Insulators do not allow electric current to flow through them.
    • Examples: plastic, rubber, glass.

Electric Circuits

  • An electric circuit is a conducting path allowing charge flow between terminals.
  • A battery produces potential difference to facilitate charge movement.
  • Voltage (V) is the potential energy difference between two points in a circuit.
  • Current (I) is the flow rate of electric charges.
  • Resistance (R) is a material's resistance to charge flow.
  • Voltage is directly proportional to current and inversely proportional to resistance (Ohm's Law : V = IR).

Electric Current

  • Electric current is the flow of charged particles.
  • Current is measured in Amperes (A).
  • 1 Ampere = 1 Coulomb/second.
  • Direct Current (DC) flows in one direction.
  • Alternating Current (AC) changes direction periodically.

Resistivity

  • Resistivity (ρ) is a property indicating how much a material resists current flow.
  • Materials with low resistivity are good conductors, high resistivity ones are insulators
  • The unit of resistivity is Ohm-meter (Ω-m).
  • Resistance (R) of a material depends on resistivity, length, and cross-sectional area. (R= ρL/A)

Resistors

  • A resistor is an electrical component limiting or regulating current flow.

Ohm's Law

  • Current in a closed circuit is directly proportional to voltage and inversely proportional to resistance.
  • The formula is V = IR.

Electric Power

  • Electric power (P) is the rate of energy transfer or work done (P = IV).
  • The unit of power is the Watt (W).

Series Circuits

  • Two or more loads are connected in a single loop.
  • The current through each resistor is the same.
  • The total resistance equals the sum of individual resistances.

Parallel Circuits

  • Loads are connected on separate loops.
  • The voltage across each resistor is the same.
  • Total current is sum of current through each path.
  • Reciprocal of total resistance equals sum of reciprocals of individual resistances.

Circuit Safety

  • Wet environments increase electrical shock risk.
  • Electrical equipment should be properly grounded.
  • Use circuit breakers or GFCIs to protect against electrical shock in wet areas.

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Description

Explore the fundamentals of electricity and electric circuits in this quiz. Understand key concepts such as electric charge, conductors, insulators, and Ohm's Law. Test your knowledge on how voltage, current, and resistance interact within circuits.

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