CBSE Class 10 Physics - Electricity and Magnetism
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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?

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

Who is the ampere named after?

<p>Andre Marie Ampere</p> Signup and view all the answers

What is 1 ampere?

<p>Flow of one coulomb of charge through any cross section area of a conductor per second</p> Signup and view all the answers

What is milliampere (mA)?

<p>10 power -3 amperes</p> Signup and view all the answers

What is microampere?

<p>10 power -6 A</p> Signup and view all the answers

What instrument is used to measure electric current?

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

In which direction does current flow in a circuit?

<p>From the positive terminal to the negative terminal</p> Signup and view all the answers

What is 1 coulomb of charge?

<p>Charge contained in 6 * 10 power 18 electrons</p> Signup and view all the answers

What does 'V' represent in electricity?

<p>Potential difference</p> Signup and view all the answers

What does 'W' represent in electricity?

<p>Work done</p> Signup and view all the answers

What does 'Q' represent in electric formulas?

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

What does 't' represent in electricity?

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

What is the SI unit of electric potential difference?

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

Who is the volt named after?

<p>Alessandro Volta</p> Signup and view all the answers

What instrument is used to measure potential difference?

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

What is Ohm's Law?

<p>Potential difference is directly proportional to the electric current</p> Signup and view all the answers

What is the SI unit of resistance?

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

What does 'I' represent in electrical terms?

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

What is resistance?

<p>Property of a conductor to resist the flow of charges</p> Signup and view all the answers

What is variable resistance?

<p>Regulate current without changing the voltage</p> Signup and view all the answers

What changes resistance with a?

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

What is a high resistance conductor?

<p>Poor conductor</p> Signup and view all the answers

What is a low resistance conductor?

<p>Good conductor</p> Signup and view all the answers

What is appreciable resistance in a conductor?

<p>Is called a resistor</p> Signup and view all the answers

Resistance is directly proportional to

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

Resistance is inversely proportional to

<p>Cross section area</p> Signup and view all the answers

What does an increase in resistance mean?

<p>The temperature increased</p> Signup and view all the answers

What is R proportional to?

<p>1/d squared</p> Signup and view all the answers

What is the SI unit of resistivity (rho)?

<p>Ohm meter</p> Signup and view all the answers

Metals and alloys have a resistivity between?

<p>10 power -6 to 10 power -8</p> Signup and view all the answers

Insulators have a resistivity between?

<p>10 power 12 to 10 power 17 ohm meters</p> Signup and view all the answers

Resistivity of an alloy is?

<p>Higher than the resistivity of its constituent metals</p> Signup and view all the answers

Why don't alloys burn easily?

<p>Because they don't burn/oxidize easily at high temperatures</p> Signup and view all the answers

What is tungsten used for?

<p>Used almost exclusively for filaments</p> Signup and view all the answers

What are copper and aluminum used for?

<p>Used for electrical transmission lines</p> Signup and view all the answers

What is a semiconductor?

<p>A conductor whose resistance lies between conductors and insulators</p> Signup and view all the answers

What charge does 1 electron possess?

<p>The negative charge of 1.6 * 10 power -19 Coulomb</p> Signup and view all the answers

What is the formula for rho?

<p>R pi d squared / 4l</p> Signup and view all the answers

What does 1 ohm meter refer to?

<p>The resistivity of a conductor is 1 ohm when the conductor is 1 m long with a cross section area of 1 m squared</p> Signup and view all the answers

What is 1 volt?

<p>1 volt is equal to the work done in moving 1 C of charge from one point to another</p> Signup and view all the answers

What is electric potential at a point?

<p>Is the amount of work done in moving a unit charge from infinity to that point</p> Signup and view all the answers

1 C is defined as?

<p>The quantity of charge that exerts a force of 9 * 10 power 9 newtons on an equal charge placed at a distance of 1 m</p> Signup and view all the answers

What is the best conductor of electricity?

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

Why is nichrome alloy used in electric heating appliances?

<p>It doesn't burn or oxidize easily at high temperature and it has a high resistivity</p> Signup and view all the answers

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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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.

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