Photo AI
A student rubbed a plastic rod with a cloth - AQA - GCSE Physics - Question 5 - 2022 - Paper 1
Question 5
A student rubbed a plastic rod with a cloth. The rod became negatively charged and the cloth became positively charged. Explain why the cloth became positively cha... show full transcript
Worked Solution & Example Answer:A student rubbed a plastic rod with a cloth - AQA - GCSE Physics - Question 5 - 2022 - Paper 1
Step 1
Explain why the cloth became positively charged.
Answer
When the student rubs the plastic rod with the cloth, electrons are transferred from the cloth to the rod. Since electrons are negatively charged, the loss of electrons from the cloth results in an excess of positive charges (protons) relative to the remaining electrons on the cloth, rendering it positively charged.
Step 2
Explain why the reading on the balance increases.
Answer
The reading on the balance increases due to the additional downward force exerted on the balance. The rod being held above is negatively charged, and like charges repel. The repulsive force between the negatively charged rod on the balance and the one held above adds to the reading on the scale.
Step 3
Give the reason why the zero error is not important in this experiment.
Answer
The zero error is not important in this experiment because it affects all readings uniformly. Thus, any measurement error will be consistent and will not alter the relative comparisons being made between the forces.
Step 4
Explain why a spark jumps between the negatively charged rod and the earthed conductor.
Answer
A spark jumps between the negatively charged rod and the earthed conductor due to the large potential difference between the two objects. This potential difference causes a strong electric field that can ionize the air, allowing charges (electrons) to move from the rod to the conductor, creating a spark.