Explain, in particle terms, how the rod acquires charge and say what happens to the cloth.
Fig. 8.1 shows a metal sphere X on a plastic stand. Explain why metals act as electrical conductors and why plastics act as electrical insulators.
Use Fig. 8.2 to show how charge is arranged on X.
A wire connected to Earth is now attached to the metal sphere as shown in Fig. 8.3. State what happens to the charges on the sphere when the earth wire is connected.
The earth wire in (ii) remains connected to the metal sphere. Describe how charge is distributed on the sphere.
The earth wire is disconnected from the sphere and then the negatively charged rod is moved away from the sphere. Explain what happens to the charges on the sphere as the charged rod is moved away.
A second metal sphere Y is negatively charged. There is an electric field surrounding Y. State what is meant by ‘electric field’.
On Fig. 8.4, draw the pattern and indicate the direction of the electric field lines around sphere Y.