Worksheet: Electromotive Force and Internal Resistance

In this worksheet, we will practice relating the electromotive force (emf) of a battery to its terminal voltage and its internal resistance.

Q1:

A battery has an electromotive force of 2.50 V. The terminal voltage of the battery is 2.42 V when it is connected to a circuit and there is a current of 435 mA in the circuit. What is the internal resistance of the battery?

Q2:

Which of the following statements is a correct description of the terminal voltage of a battery?

  • AThe terminal voltage of a battery is the voltage required to overcome its internal resistance.
  • BThe terminal voltage of a battery is the voltage of the battery when it is fully discharged.
  • CThe terminal voltage of a battery is the voltage that it applies across a circuit to which it is connected.
  • DThe terminal voltage of a battery is the potential difference across its terminals when it is not producing any current.

Q3:

Which of the following statements is a correct description of the lost voltage of a battery?

  • AThe lost voltage of a battery is the voltage of the battery when it is fully discharged.
  • BThe lost voltage of a battery is the potential difference across its terminals when it is not producing any current.
  • CThe lost voltage of a battery is the voltage that it applies across a circuit that it is connected to.
  • DThe lost voltage of a battery is the voltage required to overcome its internal resistance.

Q4:

Which of the following statements correctly relates the electromotive force 𝜀 of a battery to the current 𝐼 through the battery, the terminal voltage 𝑉 of the battery, and the internal resistance 𝑟 of the battery?

  • A𝜀=𝑉𝐼𝑟
  • B𝜀=𝑉𝑟+𝐼
  • C𝜀=𝑉+𝐼𝑟
  • D𝑉=𝜀𝐼𝑟
  • E𝑉=𝜀𝑟+𝐼

Q5:

Which of the following statements is a correct description of the electromotive force (emf) of a battery?

  • AThe emf of a battery is the voltage that it applies across a circuit to which it is connected.
  • BThe emf of a battery is the current within the battery.
  • CThe emf of a battery is the potential difference across its terminals when it is not producing any current.
  • DThe emf of a battery is the voltage required to overcome its internal resistance.

Q6:

A circuit is powered by a battery with a terminal voltage of 2.5 V. The circuit has a resistance of 3.5 Ω and the battery has an internal resistance of 0.65 Ω. What is the electromotive force of the battery?

Q7:

A battery with an electromotive force of 4.50 V is connected to a circuit with a resistance of 2.75 Ω. The current in the circuit is 1.36 A. What is the internal resistance of the battery?

Q8:

A circuit is powered by a battery with an electromotive force of 3.6 V. The circuit has a resistance of 5.5 Ω and the battery has an internal resistance of 0.75 Ω. What is the terminal voltage of the battery?

Q9:

A battery has an internal resistance of 0.48 Ω. The electromotive force of the battery is 3.5 V. What is the terminal voltage of the battery when it is connected to a circuit and there is a current of 650 mA in the circuit?

Q10:

A battery is connected to a circuit with a resistance of 4.25 Ω. The current in the circuit is 0.755 A. The internal resistance of the battery is 0.635 Ω. What is the electromotive force of the battery?

Q11:

The graph shows the change in the current in a circuit with the terminal voltage of the battery that produces the current.

What is the electromotive force of the battery?

What is the internal resistance of the battery?

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