Like Charges Repel and Unlike Charges Attract Each Other: Experimental Verification
A charged glass rod is suspended by a silk thread, such that it swings horizontally. Now another charged glass rod is brought near the end of the suspended glass rod. It is found that the ends of the two rods repel each other (Fig 1). However, if a charged ebonite rod is brought near the end of the suspended rod, the two rods attract each other (Fig 2). The above experiment shows that like charges repel and unlike charges attract each other.
The property of attraction and repulsion between charged bodies have many applications such as electrostatic paint spraying. powder coating. fly-ash collection in chimneys. ink-jet printing and photostat copying (Xerox) etc.
(i) If a glass rod is rubbed with a silk cloth, it acquires positive charge while the silk cloth acquires an equal amount of negative charge.
(ii) If an ebonite rod is rubbed with fur, it becomes negatively charged, while the fur acquires equal amount of positive charge. This classification of positive and negative charges was termed by American scientist, Benjamin Franklin.
Thus, charging a rod by rubbing does not create electricity, but simply transfers or redistributes the charges in a material.