Question

A nuclear reactor delivers a power of 10 W. Find fuel consumed by the reactor per hour, if its efficiency is 20%: (Given, $ c=3\times {{10}^{8}}\,m/s $ )

• A. $ 2\times {{10}^{-6}}g/hr $
• B. $ 9\times {{10}^{12}}g/hr $
• C. $ 8\times {{10}^{-9}}g/hr $
• D. $ 2\times {{10}^{-9}}g/hr $

Answer 1

Answer: (D)

Having efficiency of 20% by the reactor, the fuel consumed by the reactor $ E=\frac{100\times 10}{20}=50\,J/s $ Again by mass energy equivalence relation, $ E=m{{c}^{2}} $ or $ m=\frac{E}{{{c}^{2}}} $ $ =\frac{50}{{{(3\times {{10}^{8}})}^{2}}}kg/s=\frac{50\times 3600\times {{10}^{3}}}{{{(3\times {{10}^{8}})}^{2}}}g/hr $ $ =2\times {{10}^{-9}}\,g/hr $