# Why is there a difference in measured binding energy vs formula for binding energy? [closed]

I have a question about calculating the energy release from a fusion reaction. With parameters I have been supplied the liquid drop model semi-empirical binding energy formula gives the wrong answer. Does anybody know what the reason for this is?

The fusion of two tritium nuclei (T-T fusion) is given by the equation:

(3,1)H +(3,1)H =(4,2)He + 2n

We need to find the energy release, Q. For given constants in the semi-empirical binding energy we can calculate Q as: B = 14.0A − 13.1A2/3 − 0.584*Z(Z − 1)/A1/3− 19.4(A − 2Z)2/A+(±, 0) 34/A3/4,

where A is the Atomic Number and Z is the number of protons.

I get a value of 17.71MeV. Why is this different to the actual value of 11.33 MeV?

## closed as off-topic by Emilio Pisanty, Jon Custer, Kyle Kanos, Daniel Griscom, MitchellNov 8 '17 at 15:31

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