Question

Curie is a unit of
A. Length
B. It is not any unit
C. Activity
D. Atomic number

Answer 1

Hint: One curie is equivalent to $3.7\times 10^{10}$ disintegrations per second. Here, the concept behind disintegration is radioactivity in which disintegrations per second indicate decays per second. In radioactive decay processes, activity is measured as the number of disintegrations per second or the number of unstable atomic nuclei decaying per second in a given sample.

Complete step by step solution:
The curie (symbol Ci) is a non-SI radioactivity unit that was first defined in 1910. In accordance with a notice in Nature at the time, it was to be named after Pierre Curie, but it was thought by some to be named after Marie Curie as well and is now considered to be named after both.

At the original 1910 meeting that defined the curie, it was proposed that it be equivalent to 10 nanograms of radium (a practical amount). After accepting this, Marie Curie reconsidered her decision and insisted on one gram of radium. According to Bertram Boltwood, Marie Curie believed that "the use of the name 'curie' for such an infinitesimally small quantity of anything was altogether inappropriate."

By multiplying the decay energy by approximately 5.93 mW/MeV, the power emitted in radioactive decay corresponding to one curie can be determined by calculating. The curie and becquerel units of activity also indicate the number of radioactive atoms. Since the probability of decay is a fixed physical quantity, a predictable number of atoms of a particular radionuclide will decay in a given time for a recognized number of atoms.

The specific activity of a radionuclide is the number of decays that will take place in one second in one gram of atoms of that radionuclide. Due to decay, the activity of a sample decreases over time. Radioactive decay rules can be used to convert activity to an actual number of atoms. They claim that one Ci of radioactive atoms would obey the formula,
$N\lgroup~atoms\rgroup\times\lambda\lgroup~s^{-1}\rgroup=1~Ci=3.7\times10^{10}$ disintegration per second

Hence, the correct option is C.

Note: It is to be noted that units of length are meter, centimeter, etc whereas the atomic number is the measure of the total number of protons present in an atom. Also, don’t consider that curie is not any unit just because it is a surname.