Insulators are materials in which electrons are tightly bound to atoms and unable to move freely, preventing the flow of electric current. Common examples include rubber, glass, wood, plastic, and silk. These materials have high resistance and can be easily charged by friction, retaining static charges on their surfaces. In contrast to conductors like metals (e.g., copper and silver), which allow current to flow freely due to free electrons, insulators do not conduct electricity. Interestingly, diamond, while not conducting electricity, is an excellent conductor of heat due to its strong atomic bonds. The resistivity of various materials, such as metals and graphite, varies, with metals being better conductors and insulators exhibiting high resistance.
What is an insulator?
An insulator is a material in which electrons are tightly bound to atoms and cannot move freely, preventing the flow of electric current.
Why can't current flow through insulators?
Current cannot flow through insulators because they lack free electrons that are necessary for the movement of charge.
What happens when an insulator is charged?
An insulator can be easily charged by friction, and the induced charge remains static on its surface.
What is the difference between a conductor and an insulator?
A conductor allows the flow of electric current due to free-moving electrons, while an insulator resists the flow of current due to tightly bound electrons.
Why does a diamond not conduct electricity?
Diamond does not conduct electricity because it has no free electrons to facilitate the flow of electric charge.
Which of the following materials is a poor conductor of electricity?
a) Gold
b) Graphite
c) Aluminum
d) Rubber
Answer: d) Rubber
What is the main reason why copper is used in electrical wiring?
a) It is an excellent insulator
b) It has high resistivity
c) It is a good conductor of electricity
d) It can easily be charged by friction
Answer: c) It is a good conductor of electricity
Which of these metals has the lowest resistivity?
a) Iron
b) Copper
c) Aluminum
d) Tungsten
Answer: b) Copper
What happens to the charge on an insulator when it is rubbed?
a) It becomes neutral
b) It loses its charge
c) It gains a static charge that remains on the surface
d) It conducts the charge to the ground
Answer: c) It gains a static charge that remains on the surface
Which of the following materials is NOT an insulator?
a) Glass
b) Plastic
c) Copper
d) Silk
Answer: c) Copper