Aplant has two identical standby generator units for emergency use. in the area of the generators, the normal noise level registers 81 dba on the sound-level meter with the generators turned off. when one generator switches on, the slm needle jumps to 83.6 dba. (a) perform calculations to determine what the dba reading will be when the second generator also turns on (so that both generators are on). (b) if both generators are on for a full 8-hour shift, will osha's pel be exceeded? will the al be exceeded? explain. (c) if one generator is on for half the shift and both are on for the other half, will the pel be exceeded? will the al be exceeded? explain. (d) in the absence of any plant background noise, what would be the sound level contributed by a single generator? by both generators? show calculations to explain.