The charge on an $\alpha$-particle is:

When a piece of polythene is rubbed with wool,a negative charge of $4 \times 10^{-7} \ C$ is developed on the polythene. The number of electrons transferred from wool to polythene is $\left[e = 1.6 \times 10^{-19} \ C\right]$.

Give examples of non-conductors and conductors.

If $10^{9}$ electrons move out of a body to another body every second,how much time is required to get a total charge of $1 \, C$ on the other body?

Describe the activity to construct a simple electroscope.

Discuss the historical observation of frictional electrics.