Resistance in Electric Circuits

Which of the following best describes resistance in an electric circuit?

• How easy or difficult it is for charges to pass through a component

• The speed at which current flows

• The amount of energy produced by a circuit

• The number of components in a circuit

What is the equation to calculate resistance?

• Resistance = potential difference (V) / current (A)

• Resistance = current (A) / potential difference (V)

• Resistance = power (W) / current (A)

• Resistance = current (A) × potential difference (V)

If a bulb in a circuit has a current of 0.6 A and a potential difference of 12 V, what is its resistance?

• 20 Ω

• 7.2 Ω

• 0.05 Ω

• 12.6 Ω

Why does the current decrease when more bulbs are added in a series circuit?

• Because resistance increases

• Because voltage increases

• Because the battery is removed

• Because the wires are shorter

Which instrument can be used to measure the current in a circuit?

• Ammeter

• Voltmeter

• Thermometer

• Barometer

What does the diagram illustrate about the circuits?

• The currents are different even though the cells are the same

• The bulbs are identical in both circuits

• The wires are longer in one circuit

• The voltage is higher in one circuit

What do the marbles in the model represent when showing what happens inside a wire?

• Atoms

• Protons

• Electrons

• Neutrons

What happens to the wire when moving electrons collide with the atoms of the wire?

• The wire cools down

• The wire gets hot

• The wire changes color

• The wire breaks

What does the height of the slope in the marble model represent in an electric circuit?

• The current

• The resistance

• The potential difference

• The length of the wire

What is an insulator?

• A material that allows electricity to flow easily

• A material with low resistance

• A material with high resistance that contains few free electrons

• A material that is magnetic