Question

Uranium-235 has a half-life of 700 million years. How long does it take a 100 gram sample of Uranium-235 to decay to a mass of 50 grams?

Answer 1

Hint:The half-life is the time needed for an amount of substance to reduce from its original quantity to its half quantity. It is given that the half-life of uranium-235 isotope is 700 million years.

Complete step by step answer:
It is given that the half-life time for uranium-235 is 700 million years.
The half-life is defined as the time required for the original quantity to reduce to its half quantity. The half-life is denoted by ${t^{1/2}}$.
The term half-life is applied in nuclear physics to describe how frequently the unstable atom undergoes radioactive decay. The half-life of the radioactive compound is a constant which measures the time required by the substance to reduce by half of its quantity by the consequence of decay and as a result emits radiation.
The radioactive decay is a first-order reaction, therefore the time required by the nuclei half of the radioactive isotope to decay is constant and known as the half-life of the isotope. The half-life of the isotope helps to determine the radioactive strength of the isotope which is the number of decay takes place per unit of time.
Here, 100 gram samples of uranium-235 decayed to 50 grams, so the half-life of uranium is 700 million years.

Note:
Uranium-235 which is an isotope of uranium element is the only natural nucleus that can easily undergo fission. The application of Uranium-235 is that it can be used as a fuel in nuclear reactors and as an explosive in making atomic bombs.