9.3 Conservation of Electric Energy

• Electric potential energy is measured in Joules
• The principle of conservation of electric energy states that the total energy in a closed system remains constant
• Electric potential energy is a type of kinetic energy.

  False
• The sum of kinetic and potential energy of charges in an electric field remains constant.


  True
• In an electric circuit, the total energy is the sum of kinetic energy and electric potential energy
• What principle dictates that total energy remains constant in a system?

  Conservation of electric energy
• What is the formula for electric potential energy?

  U = qV
• The potential difference is the amount of energy required to move a unit charge between two points.
• The principle of conservation of electric energy applies in open systems.

  False
• The total energy in a closed system remains constant unless acted upon by external forces.

  True
• Kinetic energy is calculated as \( \frac{1}{2} mv^2 \).

  True
• What is the unit of potential difference?

  Volts
• Steps to solve conservation of energy problems in electric systems:

  1️⃣ Identify initial and final states

  2️⃣ Calculate initial potential and kinetic energy

  3️⃣ Calculate final potential and kinetic energy

  4️⃣ Apply conservation of energy

  5️⃣ Solve for unknown variables
• What type of energy do power generators convert into electric potential energy?

  Kinetic energy
• A charge of \( 2 \times 10^{-6} \) C is released from rest at a potential of 50 V and moves to a potential of 20 V. What is its final kinetic energy?

  60 \times 10^{-6} \, \text{J}
• Conservation of energy ensures that the total energy within a system remains constant.
• Match the concept with its description:

  Electric Potential Energy ↔️ Energy possessed by a charge in an electric field

  Equation ↔️ \( U = qV \)
• Match the concept with its equation:

  Conservation of Electric Energy ↔️ \( E_{total} = K + U = \text{constant} \)

  Kinetic Energy ↔️ \( K = \frac{1}{2} mv^2 \)

  Electric Potential Energy ↔️ \( U = qV \)
• Potential difference is measured in volts
• The total energy in a system is the sum of kinetic energy and potential energy.
• Match the energy type with its formula:

  Total Energy ↔️ E_{total} = K + U

  Kinetic Energy ↔️ K = \frac{1}{2} mv^2

  Electric Potential Energy ↔️ U = qV
• Electric potential energy is measured in joules.


  True
• Electric motors convert electric potential energy into kinetic energy.


  True