Let assume power P=1000 W Energy per hour =1000×3600 J Energy per fission =200MeV =200×1.6×10−13 J ∴ Number of fission per hour n=200×1.6×10−131000×3600 Number of mole per hour =Nn∴ Mass per hour =Nn×235 =200×1.6×10−13×6.02×10231000×3600×235=43.9×10−6 g This 43.9×10−6 g is nearest value of 40 micro gram so option (b) is correct.