The sound pressure level from a fan is measured to be 65 db at 3 m from the source. it can be assumed that the fan can be treated as a point source for the measurement. estimate the sound power of the fan if it is now placed in a 0.2 m x 0.2 m square duct. also, estimate the sound pressure level in the duct.

Acompressor compresses a gas, a pump compresses a liquid. for a given pressure ratio, why does it take more work to compress a gas in a compressor than a liquid in a pump? a)- for a given pressure ratio the average specific volume for a gas is much higher than the average specific volume for a liquid. b)- there is no difference. the only difference is the amount of heat generated (not work) c)- for a given pressure ratio the average volurge for a gas is much higher than the average volume for a liquid. d)-there is no difference