Static Electricity

taught by Math Arena

Course description


This course is targeted at Singapore Cambridge GCE O level students, but is also relevant to IGCSE students and Singapore's Integrated program students.

Once when doing a project, I nearly damaged a vital electronic component. All I did was touch it. Apparently, electrical charges had built up on my body as I was moving around the office - charges which turned into a current when my finger came in contact with the device. Fortunately, the current was small enough and none electrical connections melted. Still, this incident highlights what can happen if we're not careful about static electricity. In this course, we will be exploring some of the phenomena related to static electricity to help you understand more about what's actually going on.

Course Content

You will learn:

  • How to charge stuff by friction
  • How to charge stuff by induction
  • What happens when you put charged stuff next to each other
  • What happens when you put charged stuff inside a metal container
  • Some of what happens during a lightning strike (we can't tell you everything because nobody really knows what's going on)
  • How to bend water
  • The weird and interesting ways that people use static electricity, including using static electricity to paint bicycles.
  • Other cool stuff! (Some of the videos in this course are marked as "explanation videos", which go into greater depth on the topics covered. We try to bring in out-of-syllabus concepts where possible to make things more interesting and give a more complete understanding of the topic)

A link to the full O level Physics syllabus can be found here

Course Prerequisites

You will need to know:

  • A little bit about atomic structure
  • How to watch videos on your computer
Math Arena
Math Arena

The instructor is from Math Arena.The instructor is absolutely passionate about teaching and you'll find the lessons engaging and ultimately rewarding.

Course Curriculum

Charging by induction
Q19 Which of the following statements about an electrical insulator is correct?
Q20 Two insulated and uncharged metal spheres X and Y are touching. While a positively charged rod is near X, the spheres are moved apart. After this action, X has a negative charge. What will be the charge on Y?
Q21 A metal ball is charged by induction. To do this, a charged rod is held close to one side of the ball and the other side is earthed. Which diagram shows the charge distribution at this stage of the experiment?
Q22 A negatively-charged sphere X is brought up to an identical uncharged sphere Y. Sphere Y is ‘earthed’ by touching it with a finger, which is then removed. Sphere X is then moved away from sphere Y. What is the final charge, if any, on sphere Y?
Q23 A negatively charged rod is brought near two isolated metal balls X and Y. X is then earthed momentarily as shown in the diagram. If the rod is then removed, what charge would the balls possess?
Q23 explanation
Q24 A positively charged metal sphere is placed between two uncharged metal spheres, where one of which is grounded to the earth. Which diagram correctly shows how changes are distributed on the spheres?
Q25 A conducting sphere X is charged positively. The sphere X is touched with a similar sphere Y, which is initially neutral. The spheres X and Y are then separated. What are the types of charges left on X?
Q26 In order to make both of the following two metal spheres positively charged, what should be done?
Q27 A student tries to charge an insulated neutral metal cylinder using the following steps. After this process, the cylinder would most likely be
Q28 Two metallic spheres X and Y are placed in contact, and a positively charged rod Z is then brought near them as shown below. Now, if Y is earthed without removing Z as shown, then
Q29 An electrostatically charged object will pick up small pieces of paper. Which of the following will not pick up pieces of paper?