Question

The value of 1 Curie is:
A. Activity of 1g of Uranium
B. 1 disintegration/second
C. $3.7\times {{10}^{10}}$ becquerel
D. $1.6\times {{10}^{12}}$ disintegration/second

Answer 1

Hint: We tell how 1 curie is the activity of 1 gram of radium and how much that is in disintegrations per second and if it does not match any of the options, use the other units given in the option and then pick the one which matches.

Complete step-by-step solution:
1 Curie is defined as the activity of 1 gram of radium. Its activity is approximately equal to 37 billion disintegrations per second. One disintegration per second is defined as one becquerel. So, 1 Curie will be equal to 37 billion becquerels. Hence, the correct option is C, i.e. $3.7\times {{10}^{10}}$ becquerel.
Additional Information:
Radium was discovered by Marie Curie along with her husband Pierre Curie in 1898. In their honor, the activity rate of 1 gram of radium was defined as a unit called Curie. Originally in Nature, it was defined as "the quantity or mass of radium emanation in equilibrium with one gram of radium (element)" But later on more precise calculations and measurement of the activity of radium. The activity of radium turned out to be $3.66\times {{10}^{10}}$ disintegrations per second. But the unit Curie remained the same as defined earlier. The use of this unit is discouraged but still is widely used by many people. The meeting where the unit Curie was defined originally proposed for 1 curie to be the activity of 10 nanograms of radium, but Marie Curie insisted on it being 1 gram as she thought the use of the name Curie for such a small amount of anything is inappropriate.

Note: Knowledge of activity of 1 gram of radium in disintegrations per second or the SI unit becquerel is important to find the answer to this question. Take care to take the order of magnitude correctly. The unit curie is not exactly equal to the activity of one gram of radium, but it is a close approximation.