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Electricity: Coulomb's Law


Coulomb's Law


The ancient Greeks found that a piece of amber, when rubbed became electrified and attracted pieces of straw or feathers. In 1785, Charles Coulomb describes experiments that confirmed the inverse-square force law of electricity.

Coulomb's law is the fundamental law of force. Coulomb's law discusses the force between two stationary charged particles. STATIONARY, please bear in your mind!
(we'll learn a different concept for the MOVING charges) 
Knowing that, there are two type of charges: that are positive and negative charges. The Coulomb force can be attractive and/or repulsive where it depends on the types of charges interacted.

  • Like charges repel one another
  • Opposite charges attract one another
Let's understand this example of experiment, an inflated balloon is rubbed with wool . The balloon will then stick to the wall of a room, often for hours (on a dry day). Rubbing the balloon with the wool is equivalent to taking off the negative charge from the wool  onto the balloon. The balloon is now negatively charged and it is able to attract positively charged wall. The attraction is called Coulomb force.
Image result for balloon wool paper electrostatics

Application of electrostatics:

Can you imagine the phenomena of flash during thunderstorm, minor electric shock at the supermarket trolleys?? Have you ever seen/experienced them?

During thunderstorm, there is a higher (than normal) electric field created between the charged cloud and the negatively charged earth's surface.

Thank you,

Mdm Ummi Atiah KMPk

~ May it Benefits You ➽💕

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