How much Uranium-235 would be left if the fossil were approximately 700 million years old? in mg

Question

How much Uranium-235 would be left if the fossil were approximately 700 million years old? in mg

Answer 1

That depends on how much (in mg) that you had to start with.

The half life of U-235 is about 700,000,000 years. That means that every 700,000,000 years on half of the original amount has decayed.

Dividing 700,000,000 years by 700,000,000 years gives one half life.

So...in 700,000,000 years, you have half the original amount left.

So...just multiply that by the original amount in milligrams and you have the remaining amount in milligrams