Question

$1$ Curie is:
(A) The activity of $1g$ uranium
(B) $1$ disintegration per second
(C) $3.7\times {{10}^{10}}$ becquerel
(D) $1.6\times {{10}^{12}}$ disintegration per second

Answer 1

Hint Radioactivity is the emission of radiation and subatomic particles, by an unstable atomic nucleus to give out energy so that it can attain a more stable state. The non-SI unit of radioactivity is called Curie. The SI unit is called Becquerel.
Step by step solution:
Radioactivity is the process of emission of energy in the form of radiation, accompanied by the emission of subatomic particles so that an unstable atomic nucleus can be more stable. Curie is the non-SI unit of radioactivity.
Curie is defined as the number of radioactive decays per second per gram of radium. The number of radioactive decays per gram of radium is given by $3.7\times {{10}^{10}}Bq$ (Becquerel). So, $1curie$ is given by
$1curie=3.7\times {{10}^{10}}$ radioactive decays per second.

Therefore, option (C) is the correct option.

Additional information
This non-SI unit of radioactivity was named in honor of Pierre Curie, a French physicist. It is also considered to be named in honor of the French physicist and chemist, Marie Curie who had researched in the field of radioactivity. It was both Pierre Curie and Marie Curie who first discovered radium in the year $1898$.
The size or weight of radioactive material is not a factor while talking about the radioactivity of a material. For example, a small element can have more radioactivity when compared to a heavier or bigger nucleus element.

Note
The SI unit of radioactivity is Becquerel and it is defined as one nuclear decay per second. The relation between Curie and Becquerel can be given as
$1curie=3.7\times {{10}^{10}}Bq$ And, $1Bq\approx 2.703\times {{10}^{-11}}curie$
This needs to be remembered to solve this question.