Question

A nuclear reactor delivers power of 10W, 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

The correct option is D $2\times {10}^{-9}g/hr$

As fuel consumed by the react or with efficiency 20%. Then energy will be:

$E=\frac{100\times 100}{20}=50J/s$

As $E=m{c}^2,m=\frac{E}{c^2}$

$m=\frac{50}{(3\times {10}^8{)}^2}kg/s=\frac{50\times 3600\times {10}^3}{(3\times {10}^8{)}^2}g/hr=2\times {10}^{-9}g/hr$