The eye can detect 5 x 10⁴ photons per square meter per sec of green light ($\lambda =5000\text{Å}$) while the ear can detect 10^-13(W/m²). The factor by which the eye is more sensitive as a power detector than the ear is close to

$E=\frac{12375}{5000}=2.475\mathrm{eV}\approx 4\times {10}^{-19}\mathrm{J}$

So the minimum intensity to which the eye can respond

$\begin{array}{l}{I}_{\text{Eye }}=\left(\text{ Photon flux }\right)\times \left(\text{ Energy of a photon }\right)\\ \Rightarrow I_{\text{Eye }}=\left(5\times {10}^4\right)\times \left(4\times {10}^{-19}\right)\simeq 2\times {10}^{-14}\left(\mathrm{W}/{\mathrm{m}}^2\right)\end{array}$

Now as lesser the intensity required by a detector for detection, more sensitive it will be

$\frac{S_{\text{Eye }}}{S_{\text{Ear }}}=\frac{I_{\text{Ear }}}{I_{\text{Eye }}}=\frac{{10}^{-13}}{2\times {10}^{-14}}=5$ i.e., as intensity (power) detector, the eye is five times more sensitive than ear.