It was formed by ancient volcanic eruptions.
Answer:
A. 1.64 J
Explanation:
First of all, we need to find how many moles correspond to 1.4 mg of mercury. We have:

where
n is the number of moles
m = 1.4 mg = 0.0014 g is the mass of mercury
Mm = 200.6 g/mol is the molar mass of mercury
Substituting, we find

Now we have to find the number of atoms contained in this sample of mercury, which is given by:

where
n is the number of moles
is the Avogadro number
Substituting,
atoms
The energy emitted by each atom (the energy of one photon) is

where
h is the Planck constant
c is the speed of light
is the wavelength
Substituting,

And so, the total energy emitted by the sample is

The force is given by the product of mass and the acceleration thus the force is given
8480/32 is equal to 265 kg
Its actually C. I did the question on USA test prep and it said the correct answer was C.
Answer:
The smallest separation distance between the speakers is 0.71 m.
Explanation:
Given that,
Two speakers, one directly behind the other, are each generating a 240-Hz sound wave, f = 240 Hz
Let the speed of sound is 343 m/s in air. The speed of sound is given by the formula as :

To produce destructive interference at a listener standing in front of them,

So, the smallest separation distance between the speakers is 0.71 m. Hence, this is the required solution.