Radioactivity - exam practice

Nobelium-259 has a half-life of 3,500 s.

What is the decay constant of nobelium-259?

A pure sample of nuclide X containing N nuclei has an activity A.

The half-life of X is 6,000 years.

A pure sample of nuclide Y containing 3N nuclei has an activity 6A.

What is the half-life of nuclide Y?

Cobalt-60 has a half-life of 5.27 years.

What is the total activity of 1.0 g of cobalt-60?

Which of the following best describes the decay constant for a radioisotope?

After 64 days the activity of a radioactive nuclide has fallen to one sixteenth of its original value. The half-life of the radioactive nuclide is

X and Y are two radioactive nuclides. X has a half-life of 3.0 minutes and Y has a half-life of 9.0 minutes.

Two freshly prepared samples of X and Y start decaying at the same time.

After 18 minutes the number of radioactive nuclei in both samples is the same.

The sample of Y initially contained N radioactive nuclei.

What was the initial number of radioactive nuclei in the sample of X?

The number of parent nuclei in a sample of a radioactive element is N at time t.

The radioactive element has a half-life $t_{\frac{1}{2}}$

The rate of decay is proportional to

U⁺⁺ is a doubly-ionised uranium atom. The uranium atom has a nucleon number of 235 and a proton number of 92.

In a simple model of the atom, how many particles are in this ionised atom?

Uranium-236 undergoes nuclear fission to produce barium-144, krypton-89 and three free neutrons.

What is the energy released in this process?

The table shows the masses of three particles.

What is the mass difference of the Li-7 nucleus?