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
Mention the $SI$ unit and value of fundamental charge. Write its smaller units.
Select the correct statement about electric charge
How can object be charged with contact ?
What is called earthing ? Give importance of earthing in wiring.
Why only electron can transfer from one body to another body in frictional electrics ?