Question

1. Radioactivity is produced when unstable nuclei _____.
bond together
break apart
become cooler
expand
2. Radiometric dating is possible because the rates of decay of radioactive isotopes _____.
change over time
change from place to place
are constant
vary widely
3. Radiocarbon dating is used to date _____.
recent geologic events up to 75,000 years ago
recent geologic events up to 10,000 years ago
distant geologic events more than one million years ago
all geologic events of the past

Answer 1

4. What is the currently accepted age of Earth?
about 4.6 million years old
about 10 billion years old
about 4.6 billion years old
about 5.6 billion years old
5. Which of the following lists the divisions of the geologic time scale in order of longest to shortest?
era, period, epoch
epoch, period, era
era, epoch, period
period, era, epoch
6. To determine the age of sedimentary rock, geologists must relate the sedimentary rock to _____.
datable masses of sedimentary rock
datable masses of metamorphic rock
datable masses of igneous rock
fossils

Answer 2

What do you think are the correct answers to each of these questions? What difficulty are you having?

Answer 3

all i have so far is
1=b
2=a
4=c
5=a

Answer 4

Im confused on the other two and not quite sure if the others are correct

Answer 5

2a is incorrect - the half-life of radioactive decay is a constant for a given radioisotope.
3 Carbon-14 has a half life of about 5700 years - it becomes difficult to measure accurately after about 10 half-lives.
6 - not sure, but I think c igneous rocks that can be dated using long-lived isotopes.

Answer 6

only missed one. 3 is A