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Questions and Answers
What is the S.I. unit of electric charge?
What is the S.I. unit of electric charge?
Which of the following substances is considered an electrical insulator?
Which of the following substances is considered an electrical insulator?
If 3 Coulombs of charge flows through a conductor in 3 seconds, what is the current?
If 3 Coulombs of charge flows through a conductor in 3 seconds, what is the current?
What does the term electric current refer to?
What does the term electric current refer to?
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How is electric potential defined?
How is electric potential defined?
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Which of the following statements about conductors is true?
Which of the following statements about conductors is true?
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What happens to charges of the same type when they are brought together?
What happens to charges of the same type when they are brought together?
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What is considered one ampere of electric current?
What is considered one ampere of electric current?
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What is the S.I. unit of resistance?
What is the S.I. unit of resistance?
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Which of the following factors does NOT affect the resistance of a conductor?
Which of the following factors does NOT affect the resistance of a conductor?
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According to Ohm's Law, what happens to the current if the voltage is doubled while keeping resistance constant?
According to Ohm's Law, what happens to the current if the voltage is doubled while keeping resistance constant?
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What does a rheostat primarily regulate in an electrical circuit?
What does a rheostat primarily regulate in an electrical circuit?
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What is the relationship between resistivity and temperature for materials?
What is the relationship between resistivity and temperature for materials?
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Which of the following correctly describes 1 Ohm?
Which of the following correctly describes 1 Ohm?
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In a V-I graph according to Ohm's Law, what does the slope of the line represent?
In a V-I graph according to Ohm's Law, what does the slope of the line represent?
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Which symbol represents a closed plug key or switch in a circuit diagram?
Which symbol represents a closed plug key or switch in a circuit diagram?
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What happens to the electrical resistance of copper wire as its temperature increases?
What happens to the electrical resistance of copper wire as its temperature increases?
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Which factor will decrease the resistance of a wire with fixed length?
Which factor will decrease the resistance of a wire with fixed length?
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If the length of a wire is doubled while keeping its resistance constant, what happens to its cross-sectional area?
If the length of a wire is doubled while keeping its resistance constant, what happens to its cross-sectional area?
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What is the calculated resistance of an unknown resistor given a current of 100 mA and a voltage of 4V?
What is the calculated resistance of an unknown resistor given a current of 100 mA and a voltage of 4V?
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Which property determines the electrical resistivity of a metallic wire?
Which property determines the electrical resistivity of a metallic wire?
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In terms of resistivity, if two wires are made from the same material but one wire is twice as long as the other, how do their resistivities compare?
In terms of resistivity, if two wires are made from the same material but one wire is twice as long as the other, how do their resistivities compare?
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What is the effect on resistance if the diameter of a wire is decreased while keeping its length constant?
What is the effect on resistance if the diameter of a wire is decreased while keeping its length constant?
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When comparing electrical conductivity between copper and aluminum, which statement is true?
When comparing electrical conductivity between copper and aluminum, which statement is true?
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What is the S.I. unit of potential difference?
What is the S.I. unit of potential difference?
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Which device is used to measure the potential difference in a circuit?
Which device is used to measure the potential difference in a circuit?
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What is the correct formula for voltage?
What is the correct formula for voltage?
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In which direction does conventional current flow in a circuit?
In which direction does conventional current flow in a circuit?
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What converts chemical energy into electrical energy?
What converts chemical energy into electrical energy?
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What is drift velocity?
What is drift velocity?
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Which of these components is always connected in series in a circuit?
Which of these components is always connected in series in a circuit?
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What is the function of a galvanometer?
What is the function of a galvanometer?
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Study Notes
Introduction to Electricity
- An atom has a positively charged nucleus and negatively charged electrons revolving around it
- Valence electrons in metals are free to move within the conductor and constitute an electric current
Charge
- In physics, charge (electric charge) is a fundamental property of matter that describes the presence of positive or negative electrical properties in particles
- Charge is a fundamental particle of matter
- Charge can be positive or negative
- The SI unit of charge is Coulomb (C)
- Like charges repel and unlike charges attract
Charge Calculation
- Q = n × e
- Q = total charge
- n = number of electrons
- e = charge on one electron (1.6 × 10⁻¹⁹ C)
Static and Current Electricity
- Static electricity deals with electric charges at rest
- Current electricity deals with electric charges in motion
Electric Current
- The electric current is defined as the rate of flow of electric charge through any cross section of a conductor
- Electric current (I) = Charge (Q) / Time (t)
- The SI unit of current is Ampere (A)
- 1 ampere = 1 coulomb / 1 second
Resistance (R)
- Resistance is the property of a conductor to resist the flow of charges through it
- The SI unit of resistance is Ohm (Ω)
- 1 Ohm = 1 Volt / 1 Ampere
- Resistance of a uniform metallic conductor is:
- Directly proportional to the length of the conductor
- Inversely proportional to the cross-sectional area
- Directly proportional to the temperature
- Depends on nature of material
Resistivity (ρ)
- Resistivity is the resistance offered by a wire of unit length and unit cross-sectional area
- Its SI unit is Ohm-metre (Ωm)
Factors Affecting Resistance
- The resistance of a wire is influenced by its length, cross-sectional area, temperature, and material
Rheostat
- A rheostat is a variable resistor used to regulate current without changing the voltage source
Components in Electrical Circuits
- List of components and their symbols
Ohm's Law
- The current through a conductor between two points is directly proportional to the voltage across the two points, provided external conditions remain constant
- Mathematical expression: V = IR (where R = Resistance)
V-I Graph
- The graph between voltage (V) and current (I) is a straight line. The slope of the line is equal to the resistance (R).
Electrochemical Cell (Voltaic Cell)
- A device that converts chemical energy into electrical energy
Electrical Measuring Instruments
- Galvanometer: detects current in a circuit
- Ammeter: measures current in a circuit, low resistance, connected in series
- Voltmeter: measures potential difference, high resistance, connected in parallel
Drift Velocity
- The average velocity that an electron attains inside a metallic conductor due to the application of an electric field due to the potential difference
Conventional Current Direction
- The direction of conventional current is opposite to the direction of the negatively charged electrons.
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Description
Test your knowledge on the fundamentals of electricity, including charge, electric current, and the behavior of electrons. This quiz covers key definitions, calculations, and the distinction between static and current electricity. Enhance your understanding of how electricity works in both theoretical and practical contexts.
