The activity of 1 g pure pure-235 will be greater than the same amount present as U3O8.Give reasons.

 

 

 

Though the energy liberated per fusion is smaller than energy liberated per fission,yet H-bomb is more powerful than atom bomb.Why?

Generally, pure U-235 is radioactive and decays by emitting alpha particles.

 

So pure 1gm of U-235 shows higher activity.

 

But in case of U3O8 which is ore of uranium in oxide form, contains U-atoms but these are different isotopes like U-235, U-238, U-233.

 

In U3O8 as there are various isotopes of Uranium and mainly it is U-238 which is more than 95% and is not radioactive so only small fraction of U3O8 due to U-235 shows activity.

 

 

As far as your second question is concerned its not the energy liberated per fusion or fission reaction that is important, rather its energy per nucleon that is more important and exlplains your doubt.