The eye can detect 5 x 104 photons per square metre per sec of green light (λ = 5000 Å) while the ear can detect  . The factor by which the eye is more sensitive as a power detector than the ear is close to

So the minimum intensity to which the eye can respondIEye (Photon flux) x (Energy of a photon)⇒ Now as lesser the intensity required by a detector for detection, more sensitive it will bei.e. as intensity (power) detector, the eye is five times more sensitive than ear