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.
Which among the following are insulators?
Answer & explanation
Correct answer: option 4
The correct answer is Option (4) → None of the above
Substances that let electricity pass through them easily are conductors; those that offer a high resistance to it are insulators.
Option (1) Human body — Incorrect. The human body is a conductor. So, in the passage, a metal rod held in the hand shows no sign of being charged. The charge leaks through the metal and the body to the ground.
Option (2) Animal body — Incorrect. An animal body, like the human body, conducts electricity.
Option (3) Metals — Incorrect. Metals are conductors; in the passage the copper wire carries the negative charge from the plastic rod to the pith ball.
Option (4) None of the above — Correct. The human body, the animal body and metals are all conductors, so none of the three is an insulator.
NCERT (2026-27):
Conductors and Insulators – “… Those which allow electricity to pass through them easily are called conductors. … Metals, human and animal bodies and earth are conductors.”