Question

On an average how many neutrons are emitted in the fission reaction of U - 235?

• A. 5
• B. 3.4
• C. 2.4
• D. 10

Answer 1

The correct option is C 2.4

U-235 after absorbing a neutron becomes U-236 and then this “Unstable” isotope fission to give daughter products and in the process neutrons are emitted.

Interesting finding is that every time a U-236 fissions same daughters are not formed. The pair of daughters formed is different in each fission tough few pairs are highly probable.

We can give you some examples:
${}_{92}^{236}U{\to }_{53}^{137}I{+}_{39}^{97}Y+2n$
${}_{92}^{236}U{\to }_{56}^{144}Ba{+}_{36}^{89}Kr+3n$
Here in these examples we have two or three neutrons coming out.
$Averagenoofneutrons=\frac{Totalnoofneutronsfound}{Totalnooffissionevents}$.
This is an experimental work and the number comes to be almost 2.4.
Remember these neutrons trigger the next fission reaction and we get a