Tritium (3H) decays by beta emission to 3He with a half-life of 12.26 years. A sample of a tritium-containing compound has an initially activity of...

Tritium (3H) decays by beta emission to 3He with a half-life of 12.26 years. A sample of a tritium-containing compound has an initially activity of 0.833 Bq. Calculate the decay constant (k), the number of tritium nuclei present in the sample initially and the activity of the sample after 2 years.