Given the resistivities below, which material is best described as an insulator? A. 4.5 22•m
B. 2.8 x 10-8
12.m
C. 1.7 x 10-8 2•m
D. 3.2 x 108 2.m

D) 3.2 × 10^8

Explanation: Insulators are best described as materials which are poor conductors of electricity and hence do not allow passage of electricity through them. Resistivity are hence used to describe property or characteristic of a material which does not allow the flow or passage of electric current.

In summary, materials which high resistivity values are referred to as Insulators. Conversely, those with low resistivity or high conductivity values are called conductors while those with intermediate values are named semiconductors.

In the question given above, the material with a resistivity value of 3.2 × 10^8 - - - has a very high resistivity value (320000000Ω), the other options given have very low resistivity values ; 0.0000000017, etc and are most likely to be conductors due to their excessively low resistivity values.

what experimental evidence led scientists to change from the previous model to this one?

a few of the positive particles aimed at a gold foil seemed to bounce back.

the colors of light emitted from heated atoms had very specific energies.

experiments with water vapor showed that elements combine in specific proportions.

cathode rays were bent in the same way whenever a magnet was brought near them.