A charged gold leaf electroscope has its leaves apart by certain amount having enclosed air. When the electroscope is subjected to $X$-rays, then the leaves
Further dilate
Start oscillating
Collapse
Remain unaltered
Write unit and value of fundamental electric charge.
One metallic sphere $A$ is given positive charge whereas another identical metallic sphere $B$ of exactly same mass as of $A$ is given equal amount of negative charge. Then
How does electroscope work ?
How can object be charged with contact ?
Give examples of non-conductors and conductors.