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Results for "electricity"
17 total matches📖 Lesson Notes Matches (3)
P.7
Topic 2: Electricity
Introduction to Static & Current Electricity →
1. The Fundamental Nature of Electric Charges All matter is composed of microscopic atoms consisting of positively charged ...
P.7
Topic 2: Electricity
Sources of Electricity & Chemical Cells →
2. Generating Electric Potential: Primary & Secondary Cells Electricity is not a primary energy source; it must be transf...
P.7
Topic 2: Electricity
Conductors, Insulators & Domestic Electrical Safety →
4. Electrical Resistance, Conductors & Home Safety Different materials exhibit varying degrees of opposition to the flow ...
❓ Question Bank Matches (11)
P.6
Section A (1 Mark)
Accidents and First Aid
Topical Evaluation Activity
How is a burn different from a scald?
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Correct Answer / Guide:
A burn is a skin injury caused by dry heat (hot metals, flames, acid, or electricity), whereas a scald is caused by wet/moist heat (boiling water, steam, hot porridge, or soup).
A burn is a skin injury caused by dry heat (hot metals, flames, acid, or electricity), whereas a scald is caused by wet/moist heat (boiling water, steam, hot porridge, or soup).
P.7
Section A (1 Mark)
Electricity
UNEB PLE
State the fundamental law of electrostatics concerning like and unlike charges.
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Correct Answer / Guide:
Like electric charges repel each other, while unlike electric charges attract each other.
Like electric charges repel each other, while unlike electric charges attract each other.
P.7
Section A (1 Mark)
Electricity
UNEB PLE
Give one reason why copper is the preferred metal for manufacturing electrical conducting cables in domestic installations.
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Correct Answer / Guide:
Copper is a very good conductor of electricity with low electrical resistance (and it is ductile and relatively affordable).
Copper is a very good conductor of electricity with low electrical resistance (and it is ductile and relatively affordable).
P.7
Section A (1 Mark)
Electricity
UNEB PLE
Why is an electric fuse constructed using a wire with a low melting point?
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Correct Answer / Guide:
So that it melts and breaks the circuit easily when excessive or dangerous electric current surges through.
So that it melts and breaks the circuit easily when excessive or dangerous electric current surges through.
P.7
Section A (1 Mark)
Electricity
National Mocks
Identify the chemical substance used as a depolarizer in a standard dry Leclanché cell.
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Correct Answer / Guide:
Manganese dioxide ($MnO_2$).
Manganese dioxide ($MnO_2$).
P.7
Section A (1 Mark)
Electricity
Topical Revision
In an electric circuit diagram, which instrument is always connected in series to measure electric current?
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Correct Answer / Guide:
An Ammeter.
An Ammeter.
P.7
Section A (1 Mark)
Electricity
Topical Revision
What is the color code of the earth wire in a modern standard three-pin plug?
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Correct Answer / Guide:
Green with yellow stripes (or solid green).
Green with yellow stripes (or solid green).
P.7
Section B (4 Marks)
Electricity
UNEB PLE
(a) State the difference between static electricity and current electricity.
(b) Describe how static charges are produced on a plastic ruler.
(c) State two safety precautions taken to protect tall school buildings against lightning strikes.
(b) Describe how static charges are produced on a plastic ruler.
(c) State two safety precautions taken to protect tall school buildings against lightning strikes.
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Correct Answer / Guide:
(a) Static electricity consists of electric charges at rest on a surface, whereas current electricity is the continuous flow of charges (electrons) through a conductor.
(b) By rubbing the plastic ruler vigorously with a dry cloth (or dry hair), causing transfer of electrons through friction.
(c) 1. Installing a functional lightning conductor with sharp copper spikes.
2. Ensuring the earth wire of the arrestor is deeply grounded in moist soil.
(a) Static electricity consists of electric charges at rest on a surface, whereas current electricity is the continuous flow of charges (electrons) through a conductor.
(b) By rubbing the plastic ruler vigorously with a dry cloth (or dry hair), causing transfer of electrons through friction.
(c) 1. Installing a functional lightning conductor with sharp copper spikes.
2. Ensuring the earth wire of the arrestor is deeply grounded in moist soil.
P.7
Section B (4 Marks)
Electricity
UNEB PLE
The diagram represents a simple dry cell:
(a) Name the parts marked:
(i) Outer metal casing
(ii) Central black rod
(b) What is the function of the ammonium chloride paste?
(c) Why does a dry cell eventually lose power (go flat)?
(a) Name the parts marked:
(i) Outer metal casing
(ii) Central black rod
(b) What is the function of the ammonium chloride paste?
(c) Why does a dry cell eventually lose power (go flat)?
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Correct Answer / Guide:
(a) (i) Zinc can (negative terminal). (ii) Carbon / Graphite rod with brass cap (positive terminal).
(b) It acts as the chemical electrolyte that allows ionic conduction of charges.
(c) The active chemicals (zinc and ammonium chloride) are completely consumed by the chemical reaction.
(a) (i) Zinc can (negative terminal). (ii) Carbon / Graphite rod with brass cap (positive terminal).
(b) It acts as the chemical electrolyte that allows ionic conduction of charges.
(c) The active chemicals (zinc and ammonium chloride) are completely consumed by the chemical reaction.
P.7
Section B (4 Marks)
Electricity
National Mocks
(a) Draw schematic circuit symbols for:
(i) A cell
(ii) An open switch
(b) State two advantages of connecting domestic lights in parallel rather than in series.
(i) A cell
(ii) An open switch
(b) State two advantages of connecting domestic lights in parallel rather than in series.
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Correct Answer / Guide:
(a) (i) Two parallel lines: one long thin line (+) and one short thick line (-).
(ii) A line with a gap and a raised lever not making contact.
(b) 1. Each bulb operates at full voltage and glows brightly.
2. If one bulb burns out or is switched off, the remaining bulbs in other branches stay on.
(a) (i) Two parallel lines: one long thin line (+) and one short thick line (-).
(ii) A line with a gap and a raised lever not making contact.
(b) 1. Each bulb operates at full voltage and glows brightly.
2. If one bulb burns out or is switched off, the remaining bulbs in other branches stay on.
P.7
Section B (4 Marks)
Electricity
Topical Revision
(a) What is a short circuit?
(b) State two common causes of short circuits in residential houses.
(c) Why should water never be used to extinguish an electrical fire?
(b) State two common causes of short circuits in residential houses.
(c) Why should water never be used to extinguish an electrical fire?
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Correct Answer / Guide:
(a) A short circuit is an accidental direct connection between live and neutral wires with near-zero resistance, resulting in dangerously high current flow.
(b) 1. Frayed, worn-out, or damaged insulation on cables.
2. Overloading multi-plug sockets with heavy appliances.
(c) Ordinary water contains dissolved minerals and is a good electrical conductor, which will shock and electrocute anyone attempting to put out the fire.
(a) A short circuit is an accidental direct connection between live and neutral wires with near-zero resistance, resulting in dangerously high current flow.
(b) 1. Frayed, worn-out, or damaged insulation on cables.
2. Overloading multi-plug sockets with heavy appliances.
(c) Ordinary water contains dissolved minerals and is a good electrical conductor, which will shock and electrocute anyone attempting to put out the fire.
🗂️ Key Vocabulary & Flashcards (3)
Topic 2 • Electrostatics
P.7
Static Electricity
Electric charges that accumulate on the surface of an insulator through friction and remain at rest until discharged.
Topic 2 • Current
P.7
Current Electricity
The ordered continuous flow of electrons along an electric conductor from negative to positive potential.
Topic 2 • Sources
P.7
Primary Cell
An electrochemical cell that produces electricity by irreversible chemical reactions and cannot be recharged (e.g., dry cell).