How is radiometric dating done? a. the ratio of the isotopes from two different elements is compared over time. b. the ratio of a natural isotope to a radioactively decaying isotope of the same element is compared over time. c. the ratio of two radioactive isotopes is compared over time. d. the ratio of two nondecaying isotopes is compared over time.

What type of electromagnetic wave is used in security pens? a. x-rays c. microwaves b. visible light d. ultraviolet radiation select the best answer from the choices provided

Determine the maximum r-value of the polar equation r =3+3 cos 0

Atotal charge of –6.50 µc is uniformly distributed within a sphere that has a radius of 0.150 m. what is the magnitude and direction of the electric field at 0.300 m from the surface of the sphere? a) 2.89 × 105 n/c, radially inward b) 6.49 × 105 n/c, radially outward c) 4.69 × 105 n/c, radially inward d) 9.38 × 105 n/c, radially outward e) 1.30 × 106 n/c, radially inward