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A plastic rod and a piece of cloth are both uncharged - Edexcel - GCSE Physics - Question 2 - 2015 - Paper 1
Question 2
A plastic rod and a piece of cloth are both uncharged. A student rubs the plastic rod with the cloth. The plastic rod becomes negatively charged. (i) Compared wit... show full transcript
Worked Solution & Example Answer:A plastic rod and a piece of cloth are both uncharged - Edexcel - GCSE Physics - Question 2 - 2015 - Paper 1
Step 1
(i) Compared with the plastic rod, which row of the table is correct for the charge on the cloth?
Answer
The correct answer is A: positive equal. When the plastic rod is rubbed with the cloth, the rod gains negative charge from the cloth, which implies that the cloth must lose some of its electrons, effectively becoming positively charged. Since the rod and the cloth are only exchanging charge, their sizes remain equal.
Step 2
(ii) Explain how the plastic rod becomes negatively charged.
Answer
The plastic rod becomes negatively charged through a transfer of electrons from the cloth to the rod. When the rod is rubbed with the cloth, electrons from the cloth, which is initially neutral, move to the rod. As a result, the rod gains additional electrons, resulting in an overall negative charge. Meanwhile, the cloth loses these electrons and thus becomes positively charged.