Do the resin and PVC attract or repel after rubbing against styrofoam? Why?
The concepts of electrostatics allow us to find the result for the question about the electric forces in the two tubes: The tubes are attracted by having charges of different signs.
Understanding Electrostatics
Electrostatics studies the transfer of charge between bodies when they rub together. In generating charges in insulating bodies, they are not mobile. To transfer them from one body to another, they must be in contact.
The force electric between charges is of two types:
- Attractive: If the charges are of different signs.
- Repulsive: If the charges are of the same sign.
The transferred charge depends on the bodies involved. The resin is positively charged when rubbed, PVC acquires very little charge, and polystyrene acquires a negative charge due to rubbing.
When the resin is rubbed with polystyrene, the resin acquires a positive charge, and polystyrene acquires a negative charge. Then, when PVC is rubbed with polystyrene, and the polystyrene is isolated from the ground, it shares the negative charge with PVC.
Bringing the positively charged resin closer to the slightly negatively charged PVC results in the two bodies attracting each other. This is because they have charges of different signs.
In conclusion, using the concepts of electrostatics we can determine that the resin and PVC attract each other after rubbing against styrofoam due to having charges of different signs.