Gr 9 NATURAL SCIENCES: CH 3.3 SUM Resistance
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Questions and Answers

What is the definition of resistance?

  • The flow of electrons in a conductor
  • The rate of flow of electric charge in a circuit
  • A measure of how much a material opposes the flow of electric current (correct)
  • A property of matter that causes it to experience a force in an electric field

    • What represents a low resistance environment in the break time scenario?

  • The classroom doorway
  • The narrow corridor
  • The open field (correct)
  • The school building

    • What is an electrical component that adds resistance to a circuit?

  • A conductor
  • A delocalised electron
  • A resistor (correct)
  • An electric current

    • What is the term for electrons that are not associated with a particular atom and can move freely?

    <p>Delocalised</p> Signup and view all the answers

    What is the unit of measurement for resistance?

    <p>Ohms</p> Signup and view all the answers

    What causes electrons to move towards the positive terminal, creating an electric current?

    <p>An energy source, such as a battery</p> Signup and view all the answers

    What is the term for a material that allows the flow of electric charge?

    <p>Conductor</p> Signup and view all the answers

    What opposes the flow of electrons in a circuit?

    <p>Resistance</p> Signup and view all the answers

    What is the rate at which electric charge flows through a conductor in a closed circuit?

    <p>Electric current</p> Signup and view all the answers

    What is the property of matter that causes it to experience a force in an electric field?

    <p>Electric charge</p> Signup and view all the answers

    What percentage of electrical energy is converted into light in an incandescent bulb?

    <p>10%</p> Signup and view all the answers

    What percentage of electrical energy is wasted as heat in an LED?

    <p>20%</p> Signup and view all the answers

    Which of the following factors affects the resistance of a conductor?

    <p>Type of material</p> Signup and view all the answers

    What is the relationship between current, voltage, and resistance described by?

    <p>Ohm's Law</p> Signup and view all the answers

    What is the term for the ability of a material to conduct electricity?

    <p>Resistivity</p> Signup and view all the answers

    What is the purpose of resistors in electrical circuits?

    <p>To add resistance to the circuit</p> Signup and view all the answers

    What happens to the resistance of a conductor when its thickness increases?

    <p>It decreases</p> Signup and view all the answers

    What happens when electrons moving through a conductor collide with the atoms of the material?

    <p>The material heats up</p> Signup and view all the answers

    What is the function of a rheostat in a circuit?

    <p>To control the current</p> Signup and view all the answers

    What is the effect of increasing the length of a conductor on its resistance?

    <p>It increases</p> Signup and view all the answers

    What is the purpose of using a resistor in a circuit with an LED?

    <p>To control the current flow</p> Signup and view all the answers

    What happens to the resistance of a conductor when its temperature increases?

    <p>It increases</p> Signup and view all the answers

    What is a characteristic of a diode?

    <p>It has low resistance to current flow in one direction</p> Signup and view all the answers

    Why does the filament in an incandescent bulb heat up and emit light?

    <p>Due to its high resistance</p> Signup and view all the answers

    Why are LEDs more efficient than incandescent light bulbs?

    <p>They produce more light with less electrical input energy</p> Signup and view all the answers

    What is the purpose of coiling the filament in an incandescent bulb?

    <p>To fit it into a small space</p> Signup and view all the answers

    How many primary factors affect the resistance of a conductor?

    <p>4</p> Signup and view all the answers

    What is the symbol used to represent a resistor in a circuit diagram?

    Signup and view all the answers

    What is the result of increasing the resistance in a circuit?

    <p>The current decreases</p> Signup and view all the answers

    What is the purpose of resistors in controlling the brightness of a light bulb?

    <p>To control the current flow</p> Signup and view all the answers

    What happens to the current in a circuit when the resistance is increased?

    <p>It decreases</p> Signup and view all the answers

    What is the purpose of using a resistor in a circuit with an LED?

    <p>To control the current</p> Signup and view all the answers

    What is the relationship between the resistance of a conductor and its temperature?

    <p>The resistance increases as the temperature increases</p> Signup and view all the answers

    What is the function of a rheostat in a circuit?

    <p>To control the current</p> Signup and view all the answers

    Why are LEDs more efficient than incandescent light bulbs?

    <p>LEDs produce more light with less electrical energy</p> Signup and view all the answers

    What is the result of collisions between electrons and the atoms of a conductor?

    <p>The material heats up</p> Signup and view all the answers

    What is the main reason why movement becomes restricted in the corridor and classroom doorway during school break time?

    <p>The corridor and doorway are narrower</p> Signup and view all the answers

    What is the result of connecting an energy source to a conductor?

    <p>The electrons move towards the positive terminal</p> Signup and view all the answers

    What is the purpose of a conductor in an electrical circuit?

    <p>To allow the flow of electric charge</p> Signup and view all the answers

    What is the effect of resistance on the flow of electrons in a circuit?

    <p>It decreases the flow of electrons</p> Signup and view all the answers

    What is the significance of delocalised electrons in metals?

    <p>They are not associated with a particular atom and can move freely</p> Signup and view all the answers

    What is the relationship between the flow of electrons and the electric current in a conductor?

    <p>The flow of electrons is the same as the electric current</p> Signup and view all the answers

    What is the main difference between incandescent bulbs and LEDs?

    <p>LEDs convert a higher percentage of electrical energy into light with minimal energy wasted as heat</p> Signup and view all the answers

    What is the effect of increasing the cross-sectional area of a conductor?

    <p>The resistance of the conductor decreases</p> Signup and view all the answers

    What happens to the resistance of a conductor when its length is increased?

    <p>The resistance of the conductor increases</p> Signup and view all the answers

    What is the effect of increasing the temperature of a conductor?

    <p>The resistance of the conductor increases</p> Signup and view all the answers

    Why is the filament in an incandescent bulb coiled?

    <p>To fit the filament into a small space while providing high resistance</p> Signup and view all the answers

    What is the purpose of using a Sankey diagram?

    <p>To illustrate the efficiency of energy transfer in different lighting systems</p> Signup and view all the answers

    What is the primary factor that affects the resistance of a conductor?

    <p>The type of material used</p> Signup and view all the answers

    What is the relationship between the length of a conductor and its resistance?

    <p>The longer the conductor, the higher the resistance</p> Signup and view all the answers

    What is the primary reason for resistance in a conductor?

    <p>The collisions between electrons and the atoms of the conductor</p> Signup and view all the answers

    What is the outcome of adding a resistor to a circuit?

    <p>The electric current decreases</p> Signup and view all the answers

    What is the main difference between a conductor and an insulator?

    <p>A conductor has lower resistance than an insulator</p> Signup and view all the answers

    What happens to the flow of electrons in a conductor when the resistance increases?

    <p>The flow of electrons decreases</p> Signup and view all the answers

    What is the purpose of delocalised electrons in a metal?

    <p>To allow the flow of electric current</p> Signup and view all the answers

    What occurs when an energy source is connected to a conductor?

    <p>The electrons move towards the positive terminal</p> Signup and view all the answers

    What is the main advantage of using LEDs over incandescent bulbs?

    <p>They are more energy-efficient</p> Signup and view all the answers

    What is the effect of increasing the thickness of a conductor on its resistance?

    <p>It decreases the resistance</p> Signup and view all the answers

    Why do electrons encounter more collisions as they travel through a longer conductor?

    <p>Because the conductor has a longer length</p> Signup and view all the answers

    What is the effect of increasing the temperature of a conductor on its resistance?

    <p>It increases the resistance</p> Signup and view all the answers

    What is the purpose of using a Sankey diagram in the context of energy transfer?

    <p>To illustrate the efficiency of energy transfer in different systems</p> Signup and view all the answers

    What is the relationship between the cross-sectional area of a conductor and its resistance?

    <p>A larger cross-sectional area decreases the resistance</p> Signup and view all the answers

    What is the primary factor that affects the resistance of a conductor?

    <p>All of the above</p> Signup and view all the answers

    What happens to the resistance of a conductor when its length is increased?

    <p>It increases</p> Signup and view all the answers

    What is the main reason why devices like cellphone chargers become warm during use?

    <p>Electrons colliding with the atoms of the material</p> Signup and view all the answers

    What is the primary function of a rheostat in a circuit?

    <p>To adjust the current in a circuit</p> Signup and view all the answers

    Why do LEDs only allow current to flow in one direction?

    <p>Because they have very low resistance to current flow in one direction</p> Signup and view all the answers

    What happens to the current in a circuit when the resistance is increased?

    <p>It decreases</p> Signup and view all the answers

    What is the main advantage of LEDs over incandescent bulbs?

    <p>They are more efficient</p> Signup and view all the answers

    What is the purpose of using a resistor in a circuit with an LED?

    <p>To control the current through the LED</p> Signup and view all the answers

    What happens to the movement of learners when they enter the narrow corridor and doorway during school break time?

    <p>It becomes restricted and slower</p> Signup and view all the answers

    What is the flow of electric charge in a circuit?

    <p>Electric current</p> Signup and view all the answers

    What happens when an energy source is connected to a conductor?

    <p>Electrons move towards the positive terminal</p> Signup and view all the answers

    What is the significance of delocalised electrons in metals?

    <p>They are free to move and carry electric current</p> Signup and view all the answers

    What is the effect of resistance on the flow of electrons in a circuit?

    <p>It opposes the flow of electrons</p> Signup and view all the answers

    What is the relationship between the flow of electrons and the electric current in a conductor?

    <p>The flow of electrons is proportional to the electric current</p> Signup and view all the answers

    What is the result of increasing the thickness of a conductor?

    <p>The resistance decreases</p> Signup and view all the answers

    What happens when electrons moving through a conductor collide with the atoms of the material?

    <p>The electrons decelerate</p> Signup and view all the answers

    What is the main difference between the movement of learners in the field and the corridor during school break time?

    <p>The movement is restricted in the corridor</p> Signup and view all the answers

    What is the primary purpose of a Sankey diagram in relation to lighting systems?

    <p>To compare the energy efficiency of various lighting systems</p> Signup and view all the answers

    What is the effect of increasing the length of a conductor on its resistance?

    <p>The resistance increases</p> Signup and view all the answers

    What is the relationship between the cross-sectional area of a conductor and its resistance?

    <p>As the cross-sectional area increases, the resistance decreases</p> Signup and view all the answers

    What happens to the resistance of a conductor when its temperature increases?

    <p>The resistance increases</p> Signup and view all the answers

    Why are LEDs more efficient than incandescent light bulbs?

    <p>LEDs convert a higher percentage of electrical energy into light</p> Signup and view all the answers

    What is the effect of increasing the thickness of a conductor on its resistance?

    <p>The resistance decreases</p> Signup and view all the answers

    What is the purpose of coiling the filament in an incandescent bulb?

    <p>To increase the length of the filament while keeping it compact</p> Signup and view all the answers

    What is the relationship between the type of material used in a conductor and its resistance?

    <p>Different materials have different inherent resistances</p> Signup and view all the answers

    What is the effect of increasing the resistivity of a conductor on its ability to conduct electricity?

    <p>It decreases the conductor's ability to conduct electricity</p> Signup and view all the answers

    Why do thicker wires have lower resistance than thinner wires?

    <p>Thicker wires have a larger cross-sectional area</p> Signup and view all the answers

    What is the main function of resistors in electrical circuits?

    <p>To control the current in a circuit</p> Signup and view all the answers

    What happens when electrons moving through a conductor collide with the atoms of the material?

    <p>The material heats up and generates kinetic energy</p> Signup and view all the answers

    What is the purpose of a rheostat in a circuit?

    <p>To control the current in a circuit</p> Signup and view all the answers

    What is the advantage of using LEDs over incandescent light bulbs?

    <p>LEDs produce more light with less electrical energy</p> Signup and view all the answers

    What is the characteristic of a diode?

    <p>It has high resistance to current flow in one direction</p> Signup and view all the answers

    What is the result of increasing the resistance in a circuit?

    <p>The current in the circuit decreases</p> Signup and view all the answers

    What is the purpose of using a resistor in a circuit with an LED?

    <p>To control the current flow through the LED</p> Signup and view all the answers

    What is the symbol used to represent a resistor in a circuit diagram?

    Signup and view all the answers

    What happens when the resistance of a conductor increases?

    <p>The current in the circuit decreases</p> Signup and view all the answers

    What is the purpose of using a rheostat in devices such as sound equipment?

    <p>To control the current in the circuit</p> Signup and view all the answers

    What is the primary reason for the inefficiency of incandescent bulbs?

    <p>Most of the electrical energy is wasted as heat.</p> Signup and view all the answers

    What is the effect of increasing the cross-sectional area of a conductor?

    <p>The resistance of the conductor decreases.</p> Signup and view all the answers

    Why do LEDs have a higher percentage of useful output energy compared to incandescent bulbs?

    <p>LEDs convert a higher percentage of electrical energy into light.</p> Signup and view all the answers

    What happens to the resistance of a conductor when its temperature increases?

    <p>The resistance of the conductor increases.</p> Signup and view all the answers

    What is the purpose of coiling the filament in an incandescent bulb?

    <p>To fit the filament into a small space while providing high resistance.</p> Signup and view all the answers

    What is the relationship between the length of a conductor and its resistance?

    <p>A longer conductor has higher resistance.</p> Signup and view all the answers

    What is the purpose of using a Sankey diagram?

    <p>To illustrate the efficiency of energy transfer in different lighting systems.</p> Signup and view all the answers

    What happens to the resistance of a conductor when its thickness decreases?

    <p>The resistance of the conductor increases.</p> Signup and view all the answers

    Why do thicker wires have lower resistance?

    <p>Because they have a larger cross-sectional area.</p> Signup and view all the answers

    What is the result of increasing the length of a conductor?

    <p>The resistance of the conductor increases.</p> Signup and view all the answers

    Why does the flow of electric charge become restricted in the corridor and classroom doorway during school break time?

    <p>As a result of the increase in resistance</p> Signup and view all the answers

    What is the primary reason for the movement of electrons towards the positive terminal in a circuit?

    <p>As a result of the connection to an energy source</p> Signup and view all the answers

    What is the significance of delocalised electrons in metals?

    <p>They allow the flow of electric charge</p> Signup and view all the answers

    What is the effect of increasing the length of a conductor on its resistance?

    <p>It increases the resistance</p> Signup and view all the answers

    Why do electrons moving through a conductor collide with the atoms of the material?

    <p>As a result of the resistance in the conductor</p> Signup and view all the answers

    What is the relationship between the flow of electrons and the electric current in a conductor?

    <p>The flow of electrons is the same as the electric current</p> Signup and view all the answers

    What is the effect of increasing the temperature of a conductor on its resistance?

    <p>It increases the resistance</p> Signup and view all the answers

    What is the primary function of a conductor in an electrical circuit?

    <p>To allow the flow of electric charge</p> Signup and view all the answers

    What is the result of connecting an energy source to a conductor?

    <p>It increases the electric current</p> Signup and view all the answers

    What is the effect of resistance on the flow of electrons in a circuit?

    <p>It decreases the flow of electrons</p> Signup and view all the answers

    What is the primary reason why resistors are used in electrical circuits?

    <p>To control the flow of electrons and prevent overheating</p> Signup and view all the answers

    What is the effect of increasing the resistance in a circuit?

    <p>The current in the circuit decreases</p> Signup and view all the answers

    What is the purpose of a rheostat in a circuit?

    <p>To adjust the current in the circuit</p> Signup and view all the answers

    What is the primary reason why LEDs are more efficient than incandescent bulbs?

    <p>All of the above</p> Signup and view all the answers

    What is the effect of electron collisions with the atoms of a conductor?

    <p>The conductor generates heat</p> Signup and view all the answers

    What is the purpose of using a resistor in a circuit with an LED?

    <p>To control the current flow through the LED</p> Signup and view all the answers

    What is the characteristic of a diode?

    <p>It has low resistance to current flow in one direction and high resistance in the other</p> Signup and view all the answers

    What is the result of increasing the resistance in a circuit with a rheostat?

    <p>The current in the circuit decreases</p> Signup and view all the answers

    What is the primary function of a resistor in an electrical circuit?

    <p>To control the flow of electrons and prevent overheating</p> Signup and view all the answers

    What is the relationship between input energy, output energy, and energy wasted in a system?

    <p>Input energy is converted into output energy and some energy is wasted</p> Signup and view all the answers

    What is the primary reason for the restricted movement of learners in the corridor and classroom doorway during school break time?

    <p>The physical space is narrower</p> Signup and view all the answers

    What happens to the delocalised electrons in a conductor when an energy source is connected?

    <p>They move towards the positive terminal</p> Signup and view all the answers

    What is the effect of resistance on the flow of electrons in a circuit?

    <p>It decreases the flow of electrons</p> Signup and view all the answers

    What is the significance of delocalised electrons in metals?

    <p>They can move freely and carry electric current</p> Signup and view all the answers

    What is the relationship between the flow of electrons and the electric current in a conductor?

    <p>The flow of electrons is in the same direction as the electric current</p> Signup and view all the answers

    What is the primary function of a conductor in an electrical circuit?

    <p>To allow the flow of electric charge</p> Signup and view all the answers

    What is the primary purpose of using a resistor in series with an LED?

    <p>To decrease the current flowing through the LED</p> Signup and view all the answers

    How does the resistance of a conductor change when its temperature increases?

    <p>It increases</p> Signup and view all the answers

    What is the primary function of a rheostat in a circuit?

    <p>To adjust the resistance in a circuit</p> Signup and view all the answers

    Why are LEDs more efficient than incandescent bulbs?

    <p>They convert more electrical energy into light</p> Signup and view all the answers

    What is the primary reason for using a diode in a circuit?

    <p>To control the direction of current flow</p> Signup and view all the answers

    What is the primary effect of increasing the resistance in a circuit?

    <p>The current decreases</p> Signup and view all the answers

    What is the primary cause of energy wastage in incandescent bulbs?

    <p>High energy conversion into heat</p> Signup and view all the answers

    What is the effect of increasing the cross-sectional area of a conductor on its resistance?

    <p>It decreases the resistance</p> Signup and view all the answers

    What is the primary factor that affects the resistance of a conductor, according to the formula R = ρL/A?

    <p>Cross-sectional area of the conductor</p> Signup and view all the answers

    What is the result of electrons moving through a conductor with high resistance?

    <p>Electrons move slower and less efficiently</p> Signup and view all the answers

    What is the purpose of coiling the filament in an incandescent bulb?

    <p>To increase the resistance of the filament</p> Signup and view all the answers

    What is the primary advantage of using LEDs over incandescent bulbs?

    <p>LEDs are more energy-efficient and waste less energy as heat</p> Signup and view all the answers

    What is the effect of increasing the temperature of a conductor on its resistance?

    <p>It increases the resistance</p> Signup and view all the answers

    What is the primary function of a Sankey diagram in illustrating the efficiency of energy transfer in different lighting systems?

    <p>To illustrate the energy efficiency of different lighting systems</p> Signup and view all the answers

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