An annihilator is a nonzero density distribution that produces no external field for a particular source geometry. the annihilator describes quantitatively the non-uniqueness of potential field data because any amount of the annihilator can be added to a possible solution without affecting the field of the source. find a simple annihilator (rho) for a spherical mass of radius (a) as viewed from outside the sphere. let rho represent density contrast so that rho can reach negative values.

luster is not a good characteristic to use by itself because luster is the property of minerals that indicates how much the surface of a mineral reflects light. the luster of a mineral is affected by the brilliance of the light used to observe the mineral surface.

the best answer for these questions would be:

1.            c. is smaller

2.            d) concrete operational

3.            b) interaction with the environment – the children interact with their environment can them learn more.

4.            a) parents who reason openly with children can limit a child’s cognitive ability.