Question

Define Curie.

Answer 1

A unit for the calculation of the rate of radioactive decay. Of these transformations per second, one curie is equivalent to $37$ billion ($3.7 \times {10^{10}}$).

Complete step by step answer:
One decay per second is equal to one Becquerel. The Curie, named after Pierre and Marie Curie, is an older device. A curie is roughly $1{\text{ gram}}$ of radium interaction which is equal to $3.7 \times {10^{10}}$ Becquerel. A curie is also a sum of every radionuclide that decays per second at a rate of $37$ billion disintegrations.

Additional Information:
The "quantity or mass of radium emanation in equilibrium with one gram of radium" was initially presented, but is currently defined as $1{\text{ Ci}} = 3.7 \times {10^{10}}$ decays per second after some more detailed measurements of $226\;{\text{Ra}}$ activity (that has a particular frequency of $3.66 \times {10^{10}}\;{\text{Bq/g}}$).

It was suggested to make it equal to $10{\text{ nano - grams}}$ of radium (a realistic amount) at the 1910 conference that first described the curie. But Marie Curie changed her mind after initially approving this, deciding on one gram of radium. Marie Curie felt, according to Bertram Boltwood, that "the use of the word 'curie' was completely unacceptable for such an infinitesimally limited volume of anything".

$1$ Curie in modern units is around $30$ GigaBecquerel. So you'd be fried by a curie of some radioactivity (alpha, beta or gamma). It was possible to safely treat a sealed microcurie source.

Note:
The Curie (symbol- ${\text{Ci}}$) is indeed a non-SI radioactivity unit originally founded in 1910. This was named in honour for Pierre Curie, according to a note in Nature at the time, but was known at least by others to be in honour for Marie Curie too.