Question

Several groups of students were given a 2 gram (g) cube of iron and a 4 g cube of iron. They examined three physical properties of each cube: density, magnetism, and electrical conductivity. Which of the following best explains the students’ findings?

The 2 g cube had smaller values for the physical properties because the matter was squeezed together in a smaller space.
The 4 g cube had a greater density, was more magnetic, and was a stronger conductor of electricity because it occupied a larger space.
The cubes had identical properties because the amount of matter would not change these physical properties.
The density and ability to conduct electricity remained the same, but the cube was twice as magnetic because it was twice as large.

Answer 1

The best choice is:
"The cubes had identical properties because the amount of matter would not change these physical properties."

Why: density and electrical conductivity are intensive (intrinsic) properties of a material — they do not depend on the sample’s size or mass. The magnetic property normally referred to in this context (intrinsic magnetic behavior, e.g. magnetization or susceptibility) is also an intensive property; the total magnetic force of a larger piece can be greater simply because there is more material, but the material’s intrinsic magnetic behavior does not change. The other answers confuse intensive vs. extensive properties (mass and volume change, but intrinsic properties do not).