Electric Circuits Quiz

Can power sources in a circuit affect each other?

• No, they operate independently

• Yes, they can significantly impact the circuit’s behavior

• Only if they are batteries

• Only in AC circuits

Answer explanation

Power sources can interact with each other in a circuit, which can affect the overall behaviour of the circuit.

What is the role of a battery in a circuit?

• To create charge

• To provide a constant current

• To supply the energy that pushes the charge through

• To increase the circuit’s resistance

Answer explanation

Batteries are indeed a source of energy, not a charge. They provide the potential difference needed for the current to flow.

What is the ground in a circuit typically at?

• High voltage

• Zero volts

• The same potential as the power source

• Variable potential depending on the circuit design

Answer explanation

Ground can be at different potentials; it’s a reference point, and its potential is not always zero volts.

What happens to charge as it flows through a circuit?

• It gets used up

• It is conserved and moves through the circuit

• It changes form

• It dissipates as heat

Answer explanation

Charge is conserved and moves through the circuit. It’s the energy that gets transferred, not the charge itself.

What is a common error regarding the functionality of components like diodes and transistors?

• They only work in AC circuits

• They have frequency-dependent characteristics

• They are purely decorative

• They can store charge

Answer explanation

Due to their frequency-dependent characteristics, components like diodes and transistors have different behaviours in DC and AC circuits.

How fast do charges flow in a DC circuit?

• At the speed of light

• Very slowly

• Instantaneously

• At the same speed as the electric field propagates

Answer explanation

It’s important to distinguish between the drift velocity of electrons, which is slow, and the propagation speed of the electric field, which is fast.

What is a tendency when dealing with complex circuits?

• To consider all factors including wire resistance and capacitance

• To ignore real-world factors like wire resistance and inductance

• To use only linear components

• To assume all components have nonlinear characteristics

Answer explanation

It’s crucial to consider all real-world factors, such as wire resistance and capacitance, which can influence the performance of complex circuits.

What is the function of a resistor in a circuit?

• To stop the flow of charge

• To convert electrical energy into light

• To resist the flow of charge, converting electrical energy into heat

• To increase the voltage

Answer explanation

Resistors resist the flow of charge, which is why they heat up. They convert electrical energy into thermal energy.

In which direction does the actual movement of charge occur?

• From positive to negative terminal

• From negative to positive terminal

• In a circular motion

• Charge does not move

Answer explanation

Conventional current assumes that current flows from the positive to the negative terminal, but electron flow is from negative to positive.

How does the voltage drop across a resistor in a DC circuit?

• Depends on the resistor’s position in the circuit

• Is determined by the current through and the resistance of the resistor

• Is always the same regardless of the resistor’s characteristics

• Decreases over time

Answer explanation

Ohm’s Law ( V = IR ) determines the voltage drop across a resistor and is independent of its position in the circuit.