Suppose an explosion can just be heard over normal conversation with an intensity of $1.0\times {10}^{-6}\text{}{\text{\hspace{0.17em}W/m}}^2$ from 10 km away. At what distance from the explosion will the sound have an intensity that causes pain ($10\text{}{\text{\hspace{0.17em}W/m}}^2$)? Note that this calculation ignores absorption of sound energy by air and objects.

• A. $1.0\mathrm{mm}$
• B. $3.2\mathrm{mm}$
• C. $1.0\mathrm{m}$
• D. $7.0\mathrm{m}$
• E. $70\mathrm{m}$
• F. $3.2\mathrm{m}$