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