A student vigorously rubs a polytetrafluoroethylene (PTFE) rod with a dry woollen cloth. The PTFE rod acquires a net static charge of −4.8 nC-4.8\text{ nC}−4.8 nC through friction.
Which of the following statements correctly describes the transfer of charge carriers and the resulting change in mass of the PTFE rod?
(Take the elementary charge to be e=1.6×10−19 Ce = 1.6 \times 10^{-19}\text{ C}e=1.6×10−19 C and the mass of an electron to be me=9.1×10−31 kgm_e = 9.1 \times 10^{-31}\text{ kg}me=9.1×10−31 kg)
The rod lost 3.0×10103.0 \times 10^{10}3.0×1010 electrons to the cloth, and its mass decreased by 2.7×10−20 kg2.7 \times 10^{-20}\text{ kg}2.7×10−20 kg.
The rod gained 3.0×10103.0 \times 10^{10}3.0×1010 electrons from the cloth, and its mass increased by 2.7×10−20 kg2.7 \times 10^{-20}\text{ kg}2.7×10−20 kg.
The rod gained 3.0×10103.0 \times 10^{10}3.0×1010 electrons from the cloth, and its mass decreased by 2.7×10−20 kg2.7 \times 10^{-20}\text{ kg}2.7×10−20 kg.
The rod lost 3.0×10103.0 \times 10^{10}3.0×1010 protons to the cloth, and its mass decreased by 5.0×10−17 kg5.0 \times 10^{-17}\text{ kg}5.0×10−17 kg.
47 exam-style questions on Edexcel GCSE Physics 11.1 Charging by friction. Each one has a worked solution and a mark scheme showing where the marks go.