Questions and Answers
What is electric current?
Flow of electric charges called electrons in a conductor
What is an electric circuit?
A closed and continuous path of electric current consisting of different electric components
What is the SI unit of electric charge?
Coulomb
What is the SI unit of electric current?
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Who is the ampere named after?
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What is 1 ampere?
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What is milliampere (mA)?
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What is microampere?
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What instrument is used to measure electric current?
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In which direction does current flow in a circuit?
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What is 1 coulomb of charge?
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What does 'V' represent in electricity?
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What does 'W' represent in electricity?
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What does 'Q' represent in electric formulas?
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What does 't' represent in electricity?
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What is the SI unit of electric potential difference?
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Who is the volt named after?
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What instrument is used to measure potential difference?
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What is Ohm's Law?
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What is the SI unit of resistance?
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What does 'I' represent in electrical terms?
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What is resistance?
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What is variable resistance?
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What changes resistance with a?
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What is a high resistance conductor?
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What is a low resistance conductor?
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What is appreciable resistance in a conductor?
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Resistance is directly proportional to
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Resistance is inversely proportional to
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What does an increase in resistance mean?
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What is R proportional to?
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What is the SI unit of resistivity (rho)?
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Metals and alloys have a resistivity between?
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Insulators have a resistivity between?
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Resistivity of an alloy is?
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Why don't alloys burn easily?
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What is tungsten used for?
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What are copper and aluminum used for?
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What is a semiconductor?
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What charge does 1 electron possess?
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What is the formula for rho?
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What does 1 ohm meter refer to?
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What is 1 volt?
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What is electric potential at a point?
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1 C is defined as?
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What is the best conductor of electricity?
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Why is nichrome alloy used in electric heating appliances?
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Study Notes
Electric Current and Circuits
- Electric current refers to the flow of electric charges, specifically electrons, through a conductor.
- An electric circuit is a closed loop allowing continuous current flow, incorporating various electric components.
Units of Measurement
- Electric charge is measured in coulombs (C).
- Electric current's SI unit is the ampere (A).
- One ampere equals the flow of one coulomb of charge per second.
- Milliampere (mA) equals 10^-3 amperes; microampere (μA) equals 10^-6 A.
Instruments for Measurement
- An ammeter is used to measure electric current.
- A voltmeter measures potential difference across two points.
Fundamental Concepts
- Current flows from the positive terminal to the negative terminal in a circuit.
- Potential difference (V) and work done (W) are key concepts in electricity.
- Net charge is denoted as Q, while time is represented by t.
Resistance and Ohm's Law
- Resistance, measured in ohms (Ω), is the property of a conductor that opposes the flow of electric charges.
- Ohm's Law states that potential difference is directly proportional to electric current.
- Factors affecting resistance include:
- Resistance is directly proportional to the length of the conductor.
- Resistance is inversely proportional to the cross-sectional area.
Resistivity and Materials
- Resistivity (ρ) is the inherent property of a material that determines its resistance, measured in ohm-meters (Ω·m).
- Metals and alloys have resistivities ranging from 10^-6 to 10^-8 Ω·m, while insulators range from 10^12 to 10^17 Ω·m.
- Alloys generally have a higher resistivity than their constituent metals and are less prone to burning or oxidizing at high temperatures.
Applications of Materials
- Tungsten is primarily used for filaments in light bulbs due to its high melting point.
- Copper and aluminum are commonly used for electrical transmission lines because of their low resistance.
Semiconductor Characteristics
- Semiconductors have resistances between conductors and insulators, making them essential in modern electronics.
Electric Potential and Charge
- One coulomb of charge consists of approximately 6 x 10^18 electrons.
- One volt (1 V) is defined as the potential difference when one joule of work is done to move one coulomb of charge from one point to another.
- The electric potential at a point represents the work done to move a unit charge from infinity to that point.
Special Cases
- Silver is the best conductor of electricity.
- Nichrome alloy is favored in electric heating appliances due to its resistance to oxidation and high resistivity, making it safe and efficient for high-temperature applications.
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Description
Test your knowledge of key concepts in Electricity and Magnetism from the CBSE Class 10 Physics curriculum. This quiz covers essential definitions and units related to electric current and circuits, providing a solid review for students. Improve your understanding of electrical phenomena with these flashcards.