Case: Read the passage and answer the following questions

A metal rod held in hand and rubbed with wool will not show any sign of being charged. However, if a metal rod with a wooden or plastic handle is rubbed without touching its metal part, it shows signs of charging. Suppose we connect one end of a copper wire to a neutral pith ball and the other end to a negatively charged plastic rod. We will find that the pith ball acquires a negative charge. If a similar experiment is repeated with a nylon thread or a rubber band, no transfer of charge will take place from the plastic rod to the pith ball.

Assertion (A) : All substances readily allow passage of electricity through them.

Reason (R) : The substances that allows the passage of electricity through them has electric charges (electrons) that are comparatively free to move inside the material.

A is false but R is true.

Not all substances allow the passage of electricity through them.

The substances that allow the passage of electricity through them has free electrons that are comparatively free to move inside the material. They are called conductors.