The power obtained in a reactor using U235

disintegration is 1000 kW. The mass decay

of U235 per hour is

(a) 20 μg

(b) 40 μg

(c) 1 μg

(d) 10 μg

Let assume power P=1000 W

Energy per hour= 1000 x 3600 J

Energy per fission=200 MeV

                         =200×1.6×10-13 J

so, Number of fission per hour 

                     n=1000×3600200×1.6×10-13

Number of mole per hour =nN

so,   Mass per hour=nN×235

                          =1000×3600×235200×1.6×10-13×6.02×1023=43.9×10-6g

This 43.9×10-6g is nearest value of 40 micron 

so option (b) is correct.

Difficulty Level:

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