Five balls numbered $1$ to $5$ are suspended using separate threads. Pairs $(1, 2)$, $(2, 4)$ and $(4, 1)$ show electrostatic attraction, while pair $(2, 3)$ and $(4, 5)$ show repulsion. Therefore ball $1$ must be
Positively charged
Negatively charged
Neutral
Made of metal
Which is the instrument to detect the charge on the body ? Explain it with diagram.
Why does matter obtain electric charge ?
The charge on $500\,cc$ of water due to protons will be
A polythene piece rubbed with wool is found to have a negative charge of $3 \times 10^{-7} \;C$
$(a)$ Estimate the number of electrons transferred (from which to which?)
$(b)$ Is there a transfer of mass from wool to polythene?
How can you charge a metal sphere positively without touching it?