Question

The unit of activity of a radioactive source is
1. Becquerel
2. Gauss
3. Kelvin
4. Newton

Answer 1

Correct Answer - Option 1 : Becquerel

Radioactivity: 

• The atoms having a number of neutrons much more than protons are unstable. The nuclei of such atoms exhibit radioactivity.
• An example of Such an Atom is U - 238, where the number of Neutrons is 146, and the number of protons is 92.
• Radium is an important radioactive atom.
• Radioactive decay: The spontaneous breakdown of such an unstable atomic nucleus causes radioactivity.
• The process of radioactive decay as a function of time is represented by

\(ln (\frac{N}{N_0}) = - λ t\)

Unit of Radioactivity:

• Becquerel is the unit of radioactivity. 

• The number of decays per second, or activity, from a sample of radioactive nuclei, is measured in becquerel (Bq).
• It is named after Henri Becquerel.
• One Becquerel is equal to one decay per second. 

• Curie is an older unit of radioactivity. 
• It is named after Pierre and Marie Curie.
• One curie is approximately the activity of 1 gram of radium and equals (exactly) 3.7 x 10¹⁰ becquerel.

So, the correct option is Becquerel.