VanCott and Kinkade, pp. For full citation, refer to the appendix. To calculate noise dosage and equivalent noise level. To measure and quantify illumination. Noise can be measured and averaged.
Illumination varies with the distance from a lamp.
Sound Level Meter. In a room without windows or at night, select a light source. Be sure to point the noise meter perpendicular to a line from the point of measure to the source. Check if the inverse square law is true - i.e. illumination and sound level decreases as the square of the distance from the source.