He will use a radioactive element with a long half life of greater than 1 billion years
Explanation:
Rocks are an aggregation of solid mass which is usually rich in minerals. The age of rocks is established using radiometric dating method.
According to Oxford Dictionary, radiometric dating is "a method of dating geological specimens by determining the relative proportions of particular radioactive isotopes present in a sample."
The age of rocks can only be ascertained using isotopes that have very long half lives because many of these rocks are very old (aged billions of years) hence their age can only be determined using elements that has a half life greater than 1 billion years.
1-Frying an egg , heat flows from the stove into the pan and then into the egg .
2- After a car is turned on , the engine becomes hot . Heat is conducted from the engine to the hood.
