Electromotive Force and Resistance Quiz

What is the unit of electromotive force (e.m.f.)?

• Ohm

• Ampere

• Volt

• Coulomb

What does a voltmeter measure?

• Current

• Potential difference

• Resistance

• Power

How should a voltmeter be connected in a circuit to measure the potential difference across a component?

• In series with the component

• In parallel with the component

• In series with the power source

• In parallel with the power source

Which equation represents resistance (R) in terms of potential difference (V) and current (I)?

• R = V × I

• R = I / V

• R = V / I

• R = V + I

If the potential difference across a resistor is doubled, what happens to the current (assuming constant resistance)?

• It is halved

• It stays the same

• It is doubled

• It becomes zero

Which instrument is used to measure current?

• Voltmeter

• Ammeter

• Ohmmeter

• Galvanometer

In an experiment to determine resistance, what two quantities are typically measured?

• Voltage and time

• Current and resistance

• Voltage and current

• Current and power

How does increasing the length of a wire affect its resistance?

• Decreases resistance

• Increases resistance

• Has no effect on resistance

• Doubles the current

How does increasing the diameter (cross-sectional area) of a wire affect its resistance?

• Increases resistance

• Decreases resistance

• Has no effect on resistance

• Decreases current

What is the definition of 1 volt (V)?

• 1 Joule per ampere

• 1 Joule per coulomb

• 1 Coulomb per second

• 1 Ampere per ohm