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A student rubs a plastic comb with a dry cloth to give the comb a positive electric charge - Edexcel - GCSE Physics - Question 10 - 2018 - Paper 1
Question 10
A student rubs a plastic comb with a dry cloth to give the comb a positive electric charge. Figure 19 shows the charged plastic comb picking up small pieces of paper... show full transcript
Worked Solution & Example Answer:A student rubs a plastic comb with a dry cloth to give the comb a positive electric charge - Edexcel - GCSE Physics - Question 10 - 2018 - Paper 1
Step 1
Explain how rubbing the comb with a dry cloth gives the comb a positive electric charge.
Answer
When a plastic comb is rubbed with a dry cloth, electrons from the surface of the comb transfer to the particles of the cloth. This transfer occurs due to the difference in electron affinity between the materials. As electrons leave the comb, it becomes positively charged because it has lost negatively charged particles. This process is known as triboelectric charging.
Step 2
Explain how the positively-charged plastic comb picks up the small pieces of paper.
Answer
The positively charged plastic comb induces a separation of charges in the small pieces of paper. The electrons in the paper are attracted towards the comb, resulting in a temporary negative charge on the side of the paper closest to the comb. This polarization creates an attractive force between the comb and the paper, causing the paper pieces to be drawn towards the comb. This is an example of electrostatic attraction.