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Two rods A and B, made from different plastics, were given the static electrical charges shown in the diagram - Junior Cycle Science - Question a - 2008
Question a
Two rods A and B, made from different plastics, were given the static electrical charges shown in the diagram. (i) How could you have charged the rods? (ii) Descri... show full transcript
Worked Solution & Example Answer:Two rods A and B, made from different plastics, were given the static electrical charges shown in the diagram - Junior Cycle Science - Question a - 2008
Step 1
How could you have charged the rods?
Answer
The rods can be charged through the process of friction, also known as rubbing. This can be done by rubbing rod A against a cloth, which transfers electrons from the cloth to rod A, giving it a negative charge. Conversely, rod B can be charged by rubbing it with a different cloth. The different types of plastics result in one rod becoming positively charged while the other becomes negatively charged due to this process.
Step 2
Describe with the help of a labelled diagram in the box provided, how the force between the two charged rods A and B could be investigated. What result would you expect from this investigation?
Answer
To investigate the force between the two charged rods, the following steps can be followed:
- Suspend the rods: The rods should be suspended on a thread or string so they can move freely.
- Bring the rods close together: Position the charged rods A and B close to each other without touching.
- Observe the interaction: Observe the behavior of the rods. The expected result is that the rods will attract each other due to the opposite charges they hold, as one rod is negatively charged and the other is positively charged.
Step 3
Explain clearly why this only happens in dry weather.
Answer
In dry weather, the air is typically less humid, allowing static charges to build up more easily. The absence of moisture means that there are fewer water molecules in the air, which normally help to conduct electricity and allow the electric charge to disperse. Consequently, the charge can accumulate on surfaces like a supermarket trolley, leading to an electric shock when touching metal objects.