This statment is false, the pen on a seismograph does not swing freely.
If a beaker is contained with the substances nickel sulfate, zinc sulfate and solid iron, there is a substance that will be reduced in the following substances that is in it. The substance that will be reduced as it is in the beaker is the Ni^2 + or also known as the Nickel (II)
Answer: Uranium-235.
Radioactive isotopes are used to determine the age of antique objects, including fossils.
The half-life time of the radioactive elements is what permits the process of dating.
The half-life of C-14 is too short to be useful to date too old objects.
Precambrian time is the most antique era. C-14 hal-life is about 5730 years and Precambrian time is millions or billions of years ago. Given that the hal-life of U-235 is 704 million years it is appropiate to date the fossils from the Precambrian era.
