Electric Current And Current Density - Direction of Current

• Electric current is the flow of electric charge in a conductor.

• The direction of electric current is conventionally taken as the direction of flow of positive charges.

• However, since electrons are negatively charged, the actual direction of current is opposite to the direction of flow of electrons.

• In an electric circuit, the current flows from the positive terminal of the battery towards the negative terminal.

• The quantity of electric charge flowing through a particular point in a conductor per unit time is called electric current.

Example:

• Consider a circuit where electrons are flowing from left to right. The conventional direction of current will be from right to left.

• Similarly, if the current flows from top to bottom, the conventional direction of current will be from bottom to top.

Electric Current And Current Density - Definition of Current Density

• Current density is the amount of current flowing through a unit cross-sectional area of a conductor.

• It is denoted by the symbol J and is given by the formula J = I/A, where I is the current and A is the cross-sectional area.

• The SI unit of current density is Ampere per square meter (A/m^2).

• Current density can be used to study the distribution of current within a conductor.

• In a uniform conductor, the current density is constant throughout the conductor.

Example:

• Consider a wire of cross-sectional area 2 cm^2 through which a current of 5 A is flowing. The current density will be 2.5 A/m^2.

Electric Current And Current Density - Ohm’s Law

• Ohm’s law states that the current flowing through a conductor is directly proportional to the potential difference applied across it, provided the physical conditions of the conductor remain constant.

• Mathematically, Ohm’s law can be expressed as I = V/R, where I is the current, V is the potential difference, and R is the resistance.

• The SI unit of resistance is Ohm (Ω).

• Ohm’s law is valid for a conductor as long as the temperature, length, and material of the conductor remain constant.

• Ohm’s law is named after the German physicist Georg Simon Ohm who first formulated it.

Example:

• If a potential difference of 10 V is applied across a conductor with resistance 2 Ω, the current flowing through the conductor will be 5 A.

Electric Current And Current Density - Electric Power

• Electric power is the rate at which electrical energy is converted into other forms of energy in an electric circuit.

• It is denoted by the symbol P and is given by the formula P = IV, where P is power, I is the current, and V is the potential difference.

• The SI unit of electric power is Watt (W).

• Electric power can be calculated using Ohm’s law: P = V^2/R or P = I^2R.

• Electric power is the product of current and potential difference.

Example:

• If a current of 2 A flows through a circuit with a potential difference of 12 V, the electric power consumed in the circuit will be 24 W.

Electric Current And Current Density - Resistance

• Resistance is the property of a material that hinders the flow of electric current.

• It is denoted by the symbol R and is measured in Ohms (Ω).

• Resistance depends on the physical characteristics of a conductor such as length, cross-sectional area, and resistivity.

• Materials with high resistivity have high resistance, while materials with low resistivity have low resistance.

• Resistance can be calculated using Ohm’s law: R = V/I or R = ρL/A, where V is the potential difference, I is the current, ρ is the resistivity, L is the length, and A is the cross-sectional area.

Example:

• A wire with a length of 2 m, cross-sectional area of 1 cm^2, and resistivity of 3 Ω.m has a resistance of 6 Ω.

Electric Current And Current Density - Resistivity

• Resistivity is the intrinsic property of a material that determines the resistance of a conductor of that material.

• It is denoted by the symbol ρ (rho) and is measured in Ohm-meter (Ω.m).

• Resistivity depends on the type of material, temperature, and impurities present in the material.

• Materials with high resistivity have high resistance and vice versa.

• Resistivity can be used to compare the conductive properties of different materials.

Example:

• Copper has a resistivity of 1.68 x 10^-8 Ω.m, while aluminum has a resistivity of 2.82 x 10^-8 Ω.m.

Electric Current And Current Density - Superconductivity

• Superconductivity is a phenomenon where certain materials exhibit zero electrical resistance below a critical temperature.

• Superconductors have the ability to conduct electric currents without any loss of energy.

• Superconductivity was first discovered by Heike Kamerlingh Onnes in 1911.

• Superconducting materials find applications in various fields such as power transmission, magnetic levitation, and medical imaging.

• The critical temperature, below which a material becomes superconducting, varies for different materials.

Example:

• Some common superconducting materials include niobium-titanium, niobium-tin, and yttrium-barium-copper-oxide.

Electric Current And Current Density - Comparison of Conductors and Insulators

• Conductors are materials that allow the flow of electric current through them easily.

• Insulators are materials that do not allow the flow of electric current through them easily.

• Conductors have low resistance, while insulators have high resistance.

• Examples of conductors include metals such as copper and aluminum.

• Examples of insulators include rubber, glass, and plastic.

Example:

• Copper is a good conductor of electricity, while rubber is a good insulator.

Electric Current And Current Density - Effects of Electric Current

• Electric current flowing through a conductor produces various effects:

1. Heating effect: When a current flows through a conductor, it generates heat due to the resistance of the material.

2. Magnetic effect: A current-carrying conductor produces a magnetic field around it. This forms the basis of electromagnets and electric motors.

3. Chemical effect: Current can cause chemical changes in certain substances through electrolysis.

4. Physiological effect: Electric current can have harmful effects on the human body, especially at high voltages.

Example:

• The heating effect of electric current is utilized in devices such as electric heaters and electric stoves.

Electric Current And Current Density - Kirchhoff’s Laws

• Kirchhoff’s laws are fundamental principles governing the behavior of electric circuits.

1. Kirchhoff’s first law, also known as the law of conservation of charge, states that the sum of currents entering a junction is equal to the sum of currents leaving the junction.

2. Kirchhoff’s second law, also known as the voltage law, states that the sum of the potential differences in any closed loop in a circuit is equal to zero.

• Kirchhoff’s laws are named after the German physicist Gustav Kirchhoff who formulated them.

Example:

• Kirchhoff’s laws can be applied to analyze complex circuits and determine the values of currents and potential differences.

Electric Current And Current Density - Direction of Current

• Electric current is the flow of electric charge in a conductor.
• The direction of electric current is conventionally taken as the direction of flow of positive charges.
• However, since electrons are negatively charged, the actual direction of current is opposite to the direction of flow of electrons.
• In an electric circuit, the current flows from the positive terminal of the battery towards the negative terminal.
• The quantity of electric charge flowing through a particular point in a conductor per unit time is called electric current.

Example

• Consider a circuit where electrons are flowing from left to right. The conventional direction of current will be from right to left.
• Similarly, if the current flows from top to bottom, the conventional direction of current will be from bottom to top.

Electric Current And Current Density - Definition of Current Density

• Current density is the amount of current flowing through a unit cross-sectional area of a conductor.
• It is denoted by the symbol J and is given by the formula J = I/A, where I is the current and A is the cross-sectional area.
• The SI unit of current density is Ampere per square meter (A/m^2).
• Current density can be used to study the distribution of current within a conductor.
• In a uniform conductor, the current density is constant throughout the conductor.

Example

• Consider a wire of cross-sectional area 2 cm^2 through which a current of 5 A is flowing. The current density will be 2.5 A/m^2.

Electric Current And Current Density - Ohm’s Law

• Ohm’s law states that the current flowing through a conductor is directly proportional to the potential difference applied across it, provided the physical conditions of the conductor remain constant.
• Mathematically, Ohm’s law can be expressed as I = V/R, where I is the current, V is the potential difference, and R is the resistance.
• The SI unit of resistance is Ohm (Ω).
• Ohm’s law is valid for a conductor as long as the temperature, length, and material of the conductor remain constant.
• Ohm’s law is named after the German physicist Georg Simon Ohm who first formulated it.

Example

• If a potential difference of 10 V is applied across a conductor with resistance 2 Ω, the current flowing through the conductor will be 5 A.

Electric Current And Current Density - Electric Power

• Electric power is the rate at which electrical energy is converted into other forms of energy in an electric circuit.
• It is denoted by the symbol P and is given by the formula P = IV, where P is power, I is the current, and V is the potential difference.
• The SI unit of electric power is Watt (W).
• Electric power can be calculated using Ohm’s law: P = V^2/R or P = I^2R.
• Electric power is the product of current and potential difference.

Example

• If a current of 2 A flows through a circuit with a potential difference of 12 V, the electric power consumed in the circuit will be 24 W.

Electric Current And Current Density - Resistance

• Resistance is the property of a material that hinders the flow of electric current.
• It is denoted by the symbol R and is measured in Ohms (Ω).
• Resistance depends on the physical characteristics of a conductor such as length, cross-sectional area, and resistivity.
• Materials with high resistivity have high resistance, while materials with low resistivity have low resistance.
• Resistance can be calculated using Ohm’s law: R = V/I or R = ρL/A, where V is the potential difference, I is the current, ρ is the resistivity, L is the length, and A is the cross-sectional area.

Example

• A wire with a length of 2 m, cross-sectional area of 1 cm^2, and resistivity of 3 Ω.m has a resistance of 6 Ω.

Electric Current And Current Density - Resistivity

• Resistivity is the intrinsic property of a material that determines the resistance of a conductor of that material.
• It is denoted by the symbol ρ (rho) and is measured in Ohm-meter (Ω.m).
• Resistivity depends on the type of material, temperature, and impurities present in the material.
• Materials with high resistivity have high resistance and vice versa.
• Resistivity can be used to compare the conductive properties of different materials.

Example

• Copper has a resistivity of 1.68 x 10^-8 Ω.m, while aluminum has a resistivity of 2.82 x 10^-8 Ω.m.

Electric Current And Current Density - Superconductivity

• Superconductivity is a phenomenon where certain materials exhibit zero electrical resistance below a critical temperature.
• Superconductors have the ability to conduct electric currents without any loss of energy.
• Superconductivity was first discovered by Heike Kamerlingh Onnes in 1911.
• Superconducting materials find applications in various fields such as power transmission, magnetic levitation, and medical imaging.
• The critical temperature, below which a material becomes superconducting, varies for different materials.

Example

• Some common superconducting materials include niobium-titanium, niobium-tin, and yttrium-barium-copper-oxide. Electric Current And Current Density - Direction of Current

• Electric current is the flow of electric charge in a conductor.

• The direction of electric current is conventionally taken as the direction of flow of positive charges.

• However, since electrons are negatively charged, the actual direction of current is opposite to the direction of flow of electrons.

• In an electric circuit, the current flows from the positive terminal of the battery towards the negative terminal.

• The quantity of electric charge flowing through a particular point in a conductor per unit time is called electric current. Example:

• Consider a circuit where electrons are flowing from left to right. The conventional direction of current will be from right to left.

• Similarly, if the current flows from top to bottom, the conventional direction of current will be from bottom to top.

Electric Current And Current Density - Definition of Current Density

• Current density is the amount of current flowing through a unit cross-sectional area of a conductor.
• It is denoted by the symbol J and is given by the formula J = I/A, where I is the current and A is the cross-sectional area.
• The SI unit of current density is Ampere per square meter (A/m^2).
• Current density can be used to study the distribution of current within a conductor.
• In a uniform conductor, the current density is constant throughout the conductor. Example:
• Consider a wire of cross-sectional area 2 cm^2 through which a current of 5 A is flowing. The current density will be 2.5 A/m^2.

Electric Current And Current Density - Ohm’s Law

• Ohm’s law states that the current flowing through a conductor is directly proportional to the potential difference applied across it, provided the physical conditions of the conductor remain constant.
• Mathematically, Ohm’s law can be expressed as I = V/R, where I is the current, V is the potential difference, and R is the resistance.
• The SI unit of resistance is Ohm (Ω).
• Ohm’s law is valid for a conductor as long as the temperature, length, and material of the conductor remain constant.
• Ohm’s law is named after the German physicist Georg Simon Ohm who first formulated it. Example:
• If a potential difference of 10 V is applied across a conductor with resistance 2 Ω, the current flowing through the conductor will be 5 A.

Electric Current And Current Density - Electric Power

• Electric power is the rate at which electrical energy is converted into other forms of energy in an electric circuit.
• It is denoted by the symbol P and is given by the formula P = IV, where P is power, I is the current, and V is the potential difference.
• The SI unit of electric power is Watt (W).
• Electric power can be calculated using Ohm’s law: P = V^2/R or P = I^2R.
• Electric power is the product of current and potential difference. Example:
• If a current of 2 A flows through a circuit with a potential difference of 12 V, the electric power consumed in the circuit will be 24 W.

Electric Current And Current Density - Resistance

• Resistance is the property of a material that hinders the flow of electric current.
• It is denoted by the symbol R and is measured in Ohms (Ω).
• Resistance depends on the physical characteristics of a conductor such as length, cross-sectional area, and resistivity.
• Materials with high resistivity have high resistance, while materials with low resistivity have low resistance.
• Resistance can be calculated using Ohm’s law: R = V/I or R = ρL/A, where V is the potential difference, I is the current, ρ is the resistivity, L is the length, and A is the cross-sectional area. Example:
• A wire with a length of 2 m, cross-sectional area of 1 cm^2, and resistivity of 3 Ω.m has a resistance of 6 Ω.

Electric Current And Current Density - Resistivity

• Resistivity is the intrinsic property of a material that determines the resistance of a conductor of that material.
• It is denoted by the symbol ρ (rho) and is measured in Ohm-meter (Ω.m).
• Resistivity depends on the type of material, temperature, and impurities present in the material.
• Materials with high resistivity have high resistance and vice versa.
• Resistivity can be used to compare the conductive properties of different materials. Example:
• Copper has a resistivity of 1.68 x 10^-8 Ω.m, while aluminum has a resistivity of 2.82 x 10^-8 Ω.m.

Electric Current And Current Density - Superconductivity

• Superconductivity is a phenomenon where certain materials exhibit zero electrical resistance below a critical temperature.
• Superconductors have the ability to conduct electric currents without any loss of energy.
• Superconductivity was first discovered by Heike Kamerlingh Onnes in 1911.
• Superconducting materials find applications in various fields such as power transmission, magnetic levitation, and medical imaging.
• The critical temperature, below which a material becomes superconducting, varies for different materials. Example:
• Some common superconducting materials include niobium-titanium, niobium-tin, and yttrium-barium-copper-oxide.

Electric Current And Current Density - Comparison of Conductors and Insulators

• Conductors are materials that allow the flow of electric current through them easily.
• Insulators are materials that do not allow the flow of electric current through them easily.
• Conductors have low resistance, while insulators have high resistance.
• Examples of conductors include metals such as copper and aluminum.
• Examples of insulators include rubber, glass, and plastic. Example:
• Copper is a good conductor of electricity,