# Suppose, we think of fission of a ""_26^56"Fe" nucleus into two equal fragments ""_13^28"Al". Is the fission energetically possible? - Physics

Numerical

Suppose, we think of fission of a ""_26^56"Fe" nucleus into two equal fragments ""_13^28"Al". Is the fission energetically possible? Argue by working out Q of the process. Given  "m"(""_26^56 "Fe") = 55.93494 "u"  and "m"(""_13^28 "Al") = 27.98191 "u".

#### Solution

The fission of ""_26^56"Fe"  can be given as:

$\ce{^56_13 Fe -> 2 ^28_13 Al}$

It is given that:

Atomic mass of "m"(""_26^56 "Fe") = 55.93494 u

Atomic mass of m(""_13^28 "Al") = 27.98191 u

The Q-value of this nuclear reaction is given as:

Q = ["m"(""_26^56 "Fe") - 2"m"(""_13^28 "Al")]"c"^2

= [55.93494 - 2 xx 27.98191]"c"^2

= (-0.02888 " c"^2) "u"

But 1 u = 931.5 "MeV/c"^2

therefore "Q" = - 0.02888 xx 931.5 = - 26.902  MeV

The Q-value of the fission is negative. Therefore, fission is not possible energetically. For an energetically-possible fission reaction, the Q-value must be positive.

Concept: Nuclear Energy - Nuclear Fission
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#### APPEARS IN

NCERT Physics Part 1 and 2 Class 12
Chapter 13 Nuclei
Exercise | Q 13.16 | Page 463
NCERT Class 12 Physics Textbook
Chapter 13 Nuclei
Exercise | Q 16 | Page 463
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