What Is This Module About?
Nowadays, electrical appliances are commonly seen in every household. In your home, you probably have a television set, a radio, a karaoke player, a VCD player and other electrical appliances. But have you ever wondered how these appliances work? All of these need electricity to work. In this module, you will be introduced to the basic concepts of electricity. You will also learn about its uses. After going through the module, you should be able to explain common electrical phenomena like lightning and the generation of electricity. This module is made up of two lessons: Lesson 1 – Electrostatics Lesson 2 – Electricity
What Will You Learn From This Module?
After studying this module, you should be able to: ♦ ♦ ♦ ♦ ♦ define what an electric charge, an electrostatic force, electricity, a voltage, a current and a resistance are; differentiate a conductor from an insulator and a semiconductor; differentiate a series from a parallel connection; differentiate an alternating current from a direct current; and state the relationship between voltage, current and resistance in a conductor (Ohm’s law).
Let’s See What You Already Know
Before studying this module, take this simple test first to find out how much you already know about the topics in this module. Encircle the letter of the correct answer to each of the following. 1. Which of the following is not true about an electric charge? a. b. c. d. An electric charge is a fundamental quantity that is responsible for all electrical phenomena. An electric charge can have any value. A body has a negative electric charge whenever it has an excess of electrons. Electric charges can neither be created nor destroyed.
If the two electrons of a helium atom were removed, what would be its charge? a. b. c. d.
1.6 × 1019 C 3.2 × 10 C − 1.6 × 1019 C
− 3.2 × 10 −19 C
Three equally-charged bodies were hung and the interaction is depicted in the figure below. Which of the following is true? a. b. c. d. Bodies A and C must have different signs. Bodies A and B must have the same sign. The three bodies must have the same sign. Body B must have a sign that is opposite to that of Bodies A and C.
What happens to the electrostatic force between two point charges if the distance between them is doubled? a. b. c. d. The electrostatic force will also double. The electrostatic force will decrease to half its original value. The electrostatic force will decrease to one-fourth its original value. The electrostatic force will increase four times its original value.
Which of the following quantities is the same for devices connected in a series? a. b. voltage resistance c. d. potential difference current
An object has a positive electric charge. Which of the following is true? a. b. c. d. The object has an excess of electrons. The object lacks electrons. The nuclei of its atoms are positively charged. The electrons of its atoms are positively charged.
A rod with an unknown charge attracts a plastic ball. Which of the following is not a valid justification for this situation? a. b. c. d. The rod is positively charged and the ball is negatively charged. The rod is negatively charged and the ball is positively charged. The rod is negatively charged and the ball is uncharged. Both the ball and the rod are negatively charged.
Which of the following does not belong to the group? a. b. mass length c. d. resistivity cross-sectional area
Three resistors are connected in a series as shown in the figure below. Which of the following is true about the circuit? a. The resistance of the circuit is greater compared to the resistance of the resistor with the largest resistance. The current on the resistor with the least resistance is greater than that with the greatest resistance. The voltage across each element is the same. The current passing through the...