A howler monkey is the loudest land animal and under some circumstances, can be heard up to a distance of 5.0km. Assume the acoustic output of a howler to be uniform in all directions and that the threshold of hearing is 1.0*10^-12 W/m^2. The acoustic power emitted by the howler is clostest to:

A) 0.31mW
B) 1.1mW
C) 3.2mW
D) 11mW

Power emitted will be 0.314 mW

So option (A) will be correct option

Explanation:

We have given threshold hearing

Distance is given r = 5 km =5000 m

We have to find the power emitted

Power emitted is equal to

=

So power emitted will be 0.314 mW

So option (A) will be correct option.

what experimental evidence led scientists to change from the previous model to this one?

a few of the positive particles aimed at a gold foil seemed to bounce back.

the colors of light emitted from heated atoms had very specific energies.

experiments with water vapor showed that elements combine in specific proportions.

cathode rays were bent in the same way whenever a magnet was brought near them.