The sound level at 1.0 m from a certain bullfrog is 60 dB. You are surrounded by 18 such bullfrogs, all 1.0 m from you and all croaking equally loudly at the same time. What sound level are you being exposed to

The value is  

Explanation:

From the question we are told that

     The sound level is  

     The distance from the source is d = 1 m  

     The number of sources  is  n =  18

Generally the sound which the person is been exposed to is mathematically represented as

=>        

=>        

a

explanation:

no diagram was provided, but i'm guessing it's the one i've attached to my answer.

here, a mechanical force turns the rod.   this generates an electric current in the coil, which powers the bulb.