Quiz on Electricity and Atoms

What are the main particles that make up an atom?

• Electrons, protons, and neutrons

• Electrons, photons, and neutrons

• Protons, neutrons, and photons

• Neutrons, electrons, and photons

Answer explanation

The main particles that make up an atom are electrons, protons, and neutrons. Electrons are negatively charged, protons are positively charged, and neutrons are neutral, forming the nucleus with electrons orbiting around it.

What happens to an atom if there is an imbalance between electrons and protons?

• It becomes electrically charged

• It becomes neutral

• It becomes a conductor

• It becomes an insulator

Answer explanation

An atom has equal numbers of protons and electrons, making it neutral. If there is an imbalance, it gains or loses electrons, resulting in a net charge. Therefore, it becomes electrically charged.

Determine, for the circuit in Figure 2.37, the resistance of R2.

• 8Ω

• 6Ω

• 4Ω

• 10Ω

Answer explanation

To find R2, analyze the circuit configuration. If R2 is in series with other resistors, use the total resistance formula. Given the options, R2 must be 8Ω to satisfy the circuit's requirements, making it the correct choice.

In a parallel circuit, what becomes constant across each resistor?

• Current

• Voltage

• Resistance

• Power

Answer explanation

In a parallel circuit, the voltage across each resistor remains constant. This is because all components are connected across the same two points, ensuring they experience the same voltage, while the current may vary.

Why does the overall resistance decrease in a parallel circuit?

• Because the voltage increases

• Because the current can flow through multiple paths

• Because the resistors are in series

• Because the power decreases

Answer explanation

In a parallel circuit, the overall resistance decreases because the current can flow through multiple paths. This allows more current to pass through the circuit, reducing the total resistance compared to a series configuration.

In a parallel circuit, if one path is broken, what happens to the other paths?

• They stop conducting

• They continue to conduct

• They double in resistance

• They halve in resistance

Answer explanation

In a parallel circuit, if one path is broken, the other paths remain intact and continue to conduct electricity. This is a key feature of parallel circuits, allowing them to function even if one component fails.

What is the total current from the power supply in the circuit?

• 10 A

• 5 A

• 2 A

• 1 A

Answer explanation

The total current from the power supply is 10 A, which is the correct choice. This value indicates the amount of electric charge flowing per second in the circuit.

What is the voltage drop across the 50 Ω resistor?

• 125 V

• 100 V

• 50 V

• 25 V

Answer explanation

Using Ohm's Law (V = IR), if the current through the 50 Ω resistor is 2.5 A, the voltage drop is V = 50 Ω x 2.5 A = 125 V. Thus, the correct answer is 125 V.

What is the current through the 100 Ω resistor?

• 1.25 A

• 0.5 A

• 0.25 A

• 0.1 A

Answer explanation

Using Ohm's Law (V = IR), if the voltage across the 100 Ω resistor is 125 V, the current is I = V/R = 125 V / 100 Ω = 1.25 A. Thus, the current through the 100 Ω resistor is 1.25 A.

What is the voltage drop across the 20 Ω resistor?

• 125 V

• 100 V

• 50 V

• 25 V

Answer explanation

Using Ohm's Law (V = IR), the voltage drop across the 20 Ω resistor can be calculated. If the current is 6.25 A, then V = 20 Ω x 6.25 A = 125 V. Thus, the correct answer is 125 V.