5.1 Current electricity

• Electron flow is the actual movement of electrons
• Conventional current flows from the positive to the negative terminal.
• Resistance is measured in ohms.


  True
• Variable resistors can be adjusted to change their resistance.


  True
• The power rating of a resistor is the maximum power it can safely dissipate
• Electric current is the flow of electric charge
• Conventional current flows from the positive terminal to the negative terminal in a circuit.
• What is Ohm's Law?

  $V =$$IR$
• Fixed resistors have a constant resistance value.

  True
• What is tolerance in resistors?

  Allowed variation in resistance
• What is the total resistance in a series circuit?

  Sum of individual resistances
• The total resistance in a parallel circuit is calculated using the formula $1 / R_\text{total} =$$1 / R_{1} +$$1 / R_{2} +$$... +$$1 / R_{n}$, where resistance is the constant of proportionality.
• The total resistance in a parallel circuit with a 10 Ω resistor and a 20 Ω resistor is 6.67 Ω
• Match the circuit type with the correct current calculation:

  Series circuit ↔️ $I_\text{total} =$$V_\text{total} / R_\text{total}$

  Parallel circuit ↔️ $I_\text{total} =$$I_{1} +$$I_{2} +$$... +$$I_{n}$
• Electron flow occurs from the negative terminal to the positive terminal, opposite to the direction of conventional current.
• If a resistor has a resistance of 10 Ω and a current of 2 A, the voltage across it is 20 V.


  True
• Voltage measures the electric potential difference across a conductor.


  True
• What does the power rating of a resistor indicate?

  Maximum power it can dissipate
• What is the key characteristic of current in a series circuit?

  Same through all components
• What is the formula for electrical energy in joules?

  $E =$$VIt$
• What does the symbol $I$ represent in electrical circuits?


  Current
• What is the formula for electrical power in terms of current and resistance?

  $P =$$I^{2}R$
• What is the formula for electrical energy in terms of voltage, current, and time?

  E = VIt</latex>
• KCL is based on the conservation of charge
• KVL is based on the conservation of energy
• What is the first step in solving a combined circuit?

  Identify series and parallel components
• In a parallel circuit, the equivalent resistance is always greater than the individual resistances.

  False
• Conventional current is the flow of positive charge.


  True
• What type of charge carriers are present in most conductors?

  Electrons
• The formula for Ohm's Law is V = IR
• Fixed resistors have a constant resistance value
• In what direction does electron flow occur in a circuit?

  Negative to positive
• Match the type of flow with its direction:

  Conventional Current ↔️ Positive to negative

  Electron Flow ↔️ Negative to positive
• What is the voltage across a $10 \Omega$ resistor with a current of $2 A$?


  $20 V$
• The power rating of a resistor is measured in watts
• Match the circuit component with its function:

  Battery ↔️ Provides voltage

  Resistor ↔️ Limits current

  Switch ↔️ Opens or closes circuit

  LED ↔️ Emits light
• What happens to the current in a series circuit?

  Same current through each component
• What is the primary difference between a series and a parallel circuit in terms of voltage?

  Series: voltage drops add up ||| Parallel: same voltage across all components
• In a series circuit, the current path is single
• The direction of conventional current is the flow of positive charge.

  True