What is the half life of each of these radioactive isotopes?

a radioactive isotope decreased to one-fourth its original amount in 18 months.

What are some changes that can be caused by sound energy?

What process modifies light waves to vibrate in a single plane

If the spheres are now brought close to each other, but do not touch, describe how the charges will be distributed on their surfaces.

Bob has a brother, jim, who has a daughter named bertha. Bertha's daughter, jennifer, has a sister named penny. which of the following indicates the relationship between jim and penny?

Which statements describe oceanic crust? select the two correct answers. a. it is between 25 and 70 km thick. b. its age ranges from very young to more than 4 billion years old. c. it is formed at zones of volcanic activity on the ocean floor. d.

What is the concentration of H + ions at a pH = 7?

Suppose that Paul D. Trigger fires a bullet from a gun. Will the speed of the bullet leaving the muzzle will be the same as the speed of the recoiling gun? Explain.

A certain rock contains large jagged pieces of other rocks cemented by fine particles what type of rock is this explain

Could a nucleus that has one proton but no neutrons exist?

Which physical quantities has the unit kg·m·s-1?