Question 1

Which of the following best describes the relationship between current, voltage, and resistance in a conductor according to Ohm's Law?

Accepted Answer

$$I = \dfrac{V}{R}$$

Question 2

A copper wire and a steel wire of equal length and thickness are connected to the same voltage source. Which wire will have a higher current, and why?

Accepted Answer

The copper wire, because it has lower resistance.

Question 3

If a 12 V battery is connected across a resistor of $$4\ \Omega$$, what is the current through the resistor?

Accepted Answer

$$3\ 	ext{A}$$

Question 4

Which of the following statements about electric current and voltage is correct?

Accepted Answer

Current is the flow of charge, and voltage is the pressure that pushes the charge.

Question 5

A lamp rated at 60 W operates on a 120 V household circuit. What is the current through the lamp?

Accepted Answer

$$0.5\ 	ext{A}$$

Question 6

What happens to the brightness of each lamp when more lamps are added in series to a circuit?

Accepted Answer

Each lamp gets dimmer because the total resistance increases.

Question 7

Why is alternating current (AC) preferred over direct current (DC) for long-distance power transmission?

Accepted Answer

AC can be easily transformed to higher or lower voltages, reducing energy loss.

Question 8

If the resistance in a circuit is doubled while the voltage remains constant, what happens to the current?

Accepted Answer

The current is halved.

Question 9

A 9 V battery is connected to a circuit with a total resistance of $$18\ \Omega. $$How much power is dissipated in the circuit?

Accepted Answer

$$0.5\ 	ext{W}$$

Question 10

Which of the following is a safety device that can be reset after it interrupts excessive current in a circuit?

Accepted Answer

Circuit breaker

Question 11

What is the practical outcome when electrons flow through a thin lamp filament and experience resistance?

Accepted Answer

The filament produces heat and light.

Question 12

In a parallel circuit, what happens if one branch is disconnected?

Accepted Answer

The other branches continue to work.

Question 13

Which of the following best explains why wet skin is more dangerous than dry skin when touching an electrical source?

Accepted Answer

Wet skin has lower resistance, allowing more current to flow.

Question 14

A material with low resistance will have:

Accepted Answer

High conductivity

Question 15

Which of the following is true about the source of electrons in a circuit powered by a battery?

Accepted Answer

The electrons are already present in the wires; the battery supplies energy.

Question 16

If a device draws 2 A of current from a 120 V outlet, how much power does it use?

Accepted Answer

$$240\ 	ext{W}$$

Question 17

What is the main reason incandescent bulbs are used in chicken coops to keep chicks warm?

Accepted Answer

They emit most of their energy as heat.

Question 18

Which of the following is true about the current in a series circuit if one lamp burns out?

Accepted Answer

The current ceases and all lamps go out.

Question 19

If the voltage between two points in a circuit is 6 V, how much energy is given to each coulomb of charge moving between those points?

Accepted Answer

6 joules

Question 20

Which of the following best describes what travels from a light switch to a lamp when you flip the switch?

Accepted Answer

An electric field

Electric Current, Circuits, and Ohm’s Law: Study Guide

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