Paper 3 EMF

What is a source's internal resistance?

• The resistance of the materials inside the source.

• The resistance of the external circuit.

• The voltage supplied by the source.

• The current flowing through the source.

What is the internal resistance of a source equal to?

• The lost volts per unit current in the source.

• The total voltage of the source.

• The total current supplied by the source.

• The resistance of the external load.

What is the EMF of a power source?

• The amount of current it can supply

• The resistance it offers to the current

• The voltage it provides when no current is flowing

• The power it can deliver

What is the EMF of a power source?

• The work done by the source per unit charge

• The current flowing through the source

• The resistance of the source

• The power output of the source

The EMF of a power supply is equal to the potential difference across the source when:

• Maximum current flows

• No current flows

• Minimum current flows

• The source is disconnected

What is the equation used to calculate a battery's EMF from its current, load resistance, and internal resistance?

• ε = I (R - r)

• ε = I (R + r)

• ε = I (R * r)

• ε = I (R / r)

In the equation ε = I (R + r), what does 'R' represent?

• Internal Resistance

• Load Resistance

• Current

• Electromotive Force

In the equation ε = I (R + r), what does 'r' represent?

• Load Resistance

• Current

• Internal Resistance

• Electromotive Force

What is meant by the phrase 'lost volts'?

• The difference between the battery’s EMF and its terminal potential difference.

• The total voltage of the battery.

• The voltage drop across the external circuit.

• The voltage used by the battery to charge itself.

How do you calculate a battery’s EMF from its terminal potential difference, current, and internal resistance?

• EMF = Terminal Potential Difference + (Current × Internal Resistance)

• EMF = Terminal Potential Difference - (Current × Internal Resistance)

• EMF = Terminal Potential Difference × (Current + Internal Resistance)

• EMF = Terminal Potential Difference / (Current × Internal Resistance)