Rubidium-87 has a half-life of 48.1 billion years. after how many years is there 25 percent parent isotope and 75 percent daughter isotope contained in the object?

96.2 billion years.

Explanation: Half life of Rubidium-87 = 48.1 billion years

Half life is the time required to decay half of the radioactive material. Thus if 100 g of sample is present, 50 g of sample remains after half life and 50 g decays.

For 25 percent parent isotope and 75 percent daughter to remain, means 25 g of parent isotope is present and 75 g of daughter isotope is present.

This will happen after two half lives i.e 96.2 billion years and after second half life, out of 50 g , 25 g will decay and 25 g will remain.

Thus total 75 g is decayed as daughter isotope and 25 g remains as parent isotope.

biology is the study of life. it is the study of living organism.

the most common energy conversion is from kinetic energy to potential energy, and then from potential energy to kinetic energy.

later on comes the heat energy, mechanical energy, and other energy conversions.

this energy conversion is so common that we can find it in our day to day lives as well.

- one of the most common energy conversions involves the changing of potential energy to kinetic energy or kinetic energy to potential energy