Hello!
Which nuclei is NOT radioactive?
A) Am-241 B) Mg-24 C) Pu-241 D) U-238
Solving:
It is noteworthy that chemical elements located on the periodic table in the lanthanide and actinide groups are radioactive.
Am-241 (americium) belongs to the group of actinides and is a heavy and radioactive metal.
Mg-24 (magnesium) is an essential element for the body, mainly for the nervous system, in addition to synthesizing proteins and serves for hormonal control, belongs to the group of alkaline earth metals and is a non-radioactive nucleus.
Pu-241 (plutonium) is an element that is isotope of fission by plutonium, belongs to the group of actinides and is a heavy and radioactive metal.
U-238 (uranium) is an element that is isotope of non-fission uranium, belongs to the group of actinides and is a heavy and radioactive metal.
Answer:
B) Mg-24
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Answer:
The
electrons are moving through the superconductor per second.
Explanation:
Given :
Current
A
Charge of electron
C
Time
sec
From the formula of current,
Current is the number of charges flowing per unit time.

Where
number of charges means in our case number of electrons



Therefore,
electrons are moving through the superconductor per second.
Answer:
The correct answer is C. All three have equal non-zero pressure
Explanation:
Pressure is the relationship between the force and the area of a body, when the bodies are liquid the formula that
P = rho g h
Where rho is the density and h the height of the liquid
We see that for this expression the pressure does not depend on the shape of the container, but on its height, as the three vessels have the same height, the pressure at the bottom is the same.
The correct answer is C All three have equal non-zero pressure
Answer:
75.5g
Explanation:
From the ionic equation, we can write

next we find the number of charge
Note Q=it
for i=8.5A, t=3.75 to secs 3.75*60*60=13500secs
hence

Since one faraday represent one mole of electron which equal 96500C
Hence the number of mole produced by 114750C is
114750/96500=1.2mol
The mass of copper produced is

Hence the amount of copper produced is 75.5g
Answer:
0.0321 g
Explanation:
Let helium specific heat 
Assuming no energy is lost in the process, by the law of energy conservation we can state that the 20J work done is from the heat transfer to heat it up from 273K to 393K, which is a difference of ΔT = 393 - 273 = 120 K. We have the following heat transfer equation:

where
is the mass of helium, which we are looking for:
