<u>Answer:</u> The energy released for the decay of 3 grams of 230-Thorium is 
<u>Explanation:</u>
First we have to calculate the mass defect
.
The equation for the alpha decay of thorium nucleus follows:

To calculate the mass defect, we use the equation:
Mass defect = Sum of mass of product - Sum of mass of reactant


(Conversion factor:
)
To calculate the energy released, we use Einstein equation, which is:



The energy released for 230 grams of decay of thorium is 
We need to calculate the energy released for the decay of 3 grams of thorium. By applying unitary method, we get:
As, 230 grams of Th release energy of = 
Then, 3 grams of Th will release energy of = 
Hence, the energy released for the decay of 3 grams of 230-Thorium is 