<u>First law of thermodynamics:</u>
- It states that <em>"Energy neither be created nor it can be destroyed". </em>simply it converts one form of energy into another form.
- It is also known as<em> "law of conservation of energy"</em>
<u>Limitations of First law</u>
- It doesn't provide a clear idea about the direction of transfer of heat.
- It doesn't provide the information that how much heat energy converted inti work.
- Its not given any practical applications.
<u>II law of thermodynamics:</u>
It states that <em>"the total entropy of the system can never decrease over time"</em>
It is strongly proved by two laws, they are
<em>1. Kelvin-plank statement:</em>
He stated that "any engine does not give 100% efficiency". It violates the Perpetual motion of machine II kind<em>(PMM-II).</em>
<em>2. Classius statement: </em>
<em> </em><em> It states that "Heat always flows from high temperature body to low temperature body, without aid of external energy". </em>
<em> Also it stated that " Heat can also be transferred from low temperature body to high temperature body, by the aid of an external energy".</em>
<em>Applications of II law: </em>
<em>Refrigeration &Air conditioning, Heat transfer, I.C. engines, etc.</em>
Answer:
The total resistance of the wire is = 
Explanation:
Since the wires will both be in contact with the voltage source at the same time and the current flows along in their length-wise direction, the two wires will be considered to be in parallel.
Hence, for resistances in parallel, the total resistance, 

Parameters given:
Length of wire = 1 m
Cross sectional area of copper 
Cross sectional area of aluminium wire
![A_{al}= \pi( R^{2}-r^{2})\\\\ = \pi \times [ (2\times 10^{-3} )^{2}-(1\times 10^{-3} )^{2}] =9.42\times10^{-6} m^{2}\\](https://tex.z-dn.net/?f=A_%7Bal%7D%3D%20%5Cpi%28%20R%5E%7B2%7D-r%5E%7B2%7D%29%5C%5C%5C%5C%20%3D%20%5Cpi%20%5Ctimes%20%5B%20%282%5Ctimes%2010%5E%7B-3%7D%20%20%29%5E%7B2%7D-%281%5Ctimes%2010%5E%7B-3%7D%20%20%29%5E%7B2%7D%5D%20%3D9.42%5Ctimes10%5E%7B-6%7D%20m%5E%7B2%7D%5C%5C)
Resistivity of copper 
Resistivity of Aluminium 
Resistance of copper 
Resistance of aluminium 
The total resistance of the wire can be obtained as follows;


∴ The total resistance of the wire = 
The amount left of a radioactive sample amount N0 if the decay constant is 0.00125 seconds and the time is 180 seconds is 0.7999 N.
<h3>What is half-life?</h3>
The time it takes for half of the original population of radioactive atoms to decay is called the half-life. The relationship between the half-life T1/2 and the decay constant is given by T1/2 = 0.693/λ.
- N=N0e−λt
- given λ = 0.00125 seconds
- t = 180 seconds
- Now putting values.
- N=N0e−λt = 0.799
- N= 0.7999.
Read more about the radioactive :
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10 Km.
S= Speed
D= distance
T= time
S= d/t
but since you are solving for "d" the equation is d=st so you plug in 10 km/h for speed and 2.1 hours for time and just multiply them. The hours cancel out so you are left with 10km.
Force can be exerted into an object with out it moving, but if you were to move the object due to force it would be considered work. (yes, you can exert force without having the object moving)