RAS question
Carbon nanotubes are significant in nanotechnology because they are:
Correct answer: (B) Extremely strong, lightweight, and excellent electrical conductors.
Carbon nanotubes matter in nanotechnology because rolled carbon-atom tubes combine exceptional strength, low weight and high electrical conductivity.
Explanation
Carbon nanotubes are cylindrical molecules made by rolling graphene-like carbon sheets into tubes. NASA Spinoff describes the structure as carbon atoms linked by covalent bonds and rolled into a tubular form, with uniform extended bonds giving the material extraordinary strength and a high degree of electrical conductivity. That is why option B captures their technological value: CNTs are strong at very low weight, conduct electricity better than copper, and also have very high thermal conductivity. These properties make them useful in composites, electronics and energy-storage applications. The point is not that CNTs are common or medically radioactive materials; their significance comes from the rare combination of mechanical strength, lightness and conductivity at the nanoscale.
Why the other options are wrong
- (A) CNTs are expensive to produce, so cheapness and abundance do not explain their significance.
- (C) CNTs are carbon-based nanotubes valued for strength and conductivity, not radioactive materials selected for medical radioactivity.
- (D) CNTs are strong conductive nanomaterials for composites, electronics and energy storage, not biodegradable or edible substances.
Concept
This tests nanotechnology materials: how nanoscale structure changes mechanical, electrical and thermal properties. RAS often asks such Science and Technology items because material properties link basic science with applied sectors like electronics, composites and energy storage.