Select the correct answer.
a scientist compares two samples of white powder. one powder was present at the beginning of an experiment. the other powder was present at the end. she wants to determine whether a chemical reaction has occurred. she finds that neither sample bubbles or dissolves in water. she measures the mass and volume of the solids. sample one has a volume of 45 cm3 and a mass of 0.5 g. sample two has a volume of 65 cm3 and a mass of 1.3 g. what should the scientist conclude?
a.
the samples have the same color, so no chemical reaction has occurred.
b.
the two samples do not react with water, so no chemical reaction has occurred.
c.
the densities of the samples are different, so a chemical reaction has occurred.
d.
the densities of the samples are the same, so no chemical reaction has occurred.
e.
the densities of the samples are different, so no chemical reaction has occurred

The mini-refrigerator fire was most likely caused by what type of wiring?

What would be the strength of earth's gravitational field at a point where an 80.0 kg astronaut would experience a 80% reduction in weight

To understand the behavior of the electric field at the surface of a conductor, and its relationship to surface charge on the conductor. a conductor is placed in an external electrostatic field. the external field is uniform before the conductor is placed within it. the conductor is completely isolated from any source of current or charge. part a: which of the following describes the electric field inside this conductor? it is in the same direction as the original external field.it is in the opposite direction from that of the original external field.it has a direction determined entirely by the charge on its surface.it is always zero. part b: the charge density inside the conductor is: 0non-zero; but uniformnon-zero; non-uniforminfinite part c: assume that at some point just outside the surface of the conductor, the electric field has magnitude e and is directed toward the surface of the conductor. what is the charge density η on the surface of the conductor at that point? express your answer in terms of e and ϵ0