The loudness level of a sound, $D,$ in decibels, is given by the formula
$$ D=10 \log \left(10^{12} I\right) $$
where $I$ is the intensity of the sound, in watts per meter.$^{2} .$ Decibel levels range from $0,$ a barely audible sound, to $160,$ a sound resulting in a ruptured eardrum. (Any exposure to sounds of I30 decibels or higher puts a person at immediate risk for hearing damage.) Use the formula to solve
What is the decibel level of a normal conversation, $3.2 \times 10^{-6}$ watt per meter $^{2} ?$