A metal wire has a circular cross section with radius 0.800 mm. You measure the resistivity of the wire in the following way: you connect one end of the wire to one terminal of a battery that has emf 12.0 V and negligible internal resistance. To the other terminal of the battery you connect a point along the wire so that the length of wire between the battery terminals is d. You measure the current in the wire as a function of d. The currents are small, so the temperature change of the wire is very small. You plot your results as I versus 1/d and find that the data lie close to a straight line that has slope 600 A⋅m. Required:
What is the resistivity of the material of which the wire is made?

The value is  

Explanation:

From the question we are told that

   The radius is  

   The voltage of the battery is  

    The slope is  

Generally the resistance is mathematically represented as

Generally the current is mathematically represented as

=>    

=>  

Comparing this equation to that of a straight line we see that the slope is  

So    

Here A is the cross-sectional  area of the wire which is mathematically represented as

=>      

=>          

So

=>  

=>  

answer; (d) spontaneous processes are characterized by the overall conversion of order to disorder;

firearm identification is the process of analyzing the bullets and cartridge cases left at a crime scene to determine if they came from a particular firearm. marks on the bullets and cartridges may be common to every firearm of that type. these are called class characteristics.