When a glass rod is rubbed with silk, the correct answer is B.) Equal but opposite charges are produced on both. This phenomenon is a classic example of static electricity and involves the transfer of electrons between two materials. Let’s break this down to understand how it works.
The Basics of Charging by Friction
When two different materials come into contact and are then separated, electrons can be transferred from one material to the other. This process is known as triboelectric charging. In the case of a glass rod and silk, the glass rod tends to lose electrons, while the silk gains them.
What Happens During Rubbing?
- Glass Rod: As you rub the glass rod with silk, it loses electrons. This loss of negatively charged electrons results in the glass rod becoming positively charged.
- Silk: Conversely, the silk gains those electrons, leading to a negative charge on the silk.
This transfer of electrons creates equal but opposite charges on the two objects. The glass rod ends up positively charged, while the silk becomes negatively charged. This is a fundamental principle of electrostatics, where the total charge is conserved, meaning that the amount of charge lost by one object is equal to the amount gained by the other.
Understanding Charge Conservation
To visualize this, think of it like a seesaw. If one side goes up (loses electrons), the other side must go down (gains electrons) to maintain balance. In our case, the glass rod and silk are the two sides of the seesaw, and the charges are balanced in terms of magnitude but opposite in nature.
Real-World Applications
This principle of charging by friction is not just a theoretical concept; it has practical applications. For instance, it explains why your hair stands up after you take off a wool hat in winter. The hat transfers electrons to your hair, leaving your hair positively charged and causing it to repel from other positively charged strands.
In summary, when a glass rod is rubbed with silk, both objects acquire charges that are equal in magnitude but opposite in sign. This interaction illustrates the fundamental principles of electrostatics and the conservation of charge, which are essential concepts in physics and chemistry.
