An astronomer wants to visualize the relative distances between planets in our solar system. A biologist wants to examine the br
2 answers:
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Answer:
each resistor is 540 Ω
Explanation:
Let's assign the letter R to the resistance of the three resistors involved in this problem. So, to start with, the three resistors are placed in parallel, which results in an equivalent resistance defined by the formula:
Therefore, R/3 is the equivalent resistance of the initial circuit.
In the second circuit, two of the resistors are in parallel, so they are equivalent to:
and when this is combined with the third resistor in series, the equivalent resistance () of this new circuit becomes the addition of the above calculated resistance plus the resistor R (because these are connected in series):
The problem states that the difference between the equivalent resistances in both circuits is given by:
so, we can replace our found values for the equivalent resistors (which are both in terms of R) and solve for R in this last equation:
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