Answer:
The shorter the blades(edges) are the more pressure can be applied. Because iron is a more dense and tougher material the edges must be short in order to provide enough pressure/force to break the bonds within the atoms.
Explanation:
To solve this problem we will apply the relation of Ohm's law, at the same time we will use the concept of resistance in a cable, resistivity and potential difference.
According to Ohm's law we have to
![V= IR](https://tex.z-dn.net/?f=V%3D%20IR)
Here,
V = Voltage
I = Current
R = Resistance
At the same time resistance can be described as
![R = \frac{\rho l}{A}](https://tex.z-dn.net/?f=R%20%3D%20%5Cfrac%7B%5Crho%20l%7D%7BA%7D)
Here,
= Resistivity of the material
l = Length of the specimen
A = Cross-sectional area
From the above expression we can write the current as,
![I = \frac{V}{R}](https://tex.z-dn.net/?f=I%20%3D%20%5Cfrac%7BV%7D%7BR%7D)
![I = \frac{V}{\frac{\rho l}{A}}](https://tex.z-dn.net/?f=I%20%3D%20%5Cfrac%7BV%7D%7B%5Cfrac%7B%5Crho%20l%7D%7BA%7D%7D)
![I =\frac{VA}{\rho l}](https://tex.z-dn.net/?f=I%20%3D%5Cfrac%7BVA%7D%7B%5Crho%20l%7D)
Replacing we have that,
![I = \frac{(0.8V)(0.4*10^{-6}m^2)}{(5.6*10^{-8}\Omega \cdot m)(1.5m)}](https://tex.z-dn.net/?f=I%20%3D%20%5Cfrac%7B%280.8V%29%280.4%2A10%5E%7B-6%7Dm%5E2%29%7D%7B%285.6%2A10%5E%7B-8%7D%5COmega%20%5Ccdot%20m%29%281.5m%29%7D)
![I = 3.809A](https://tex.z-dn.net/?f=I%20%3D%203.809A)
Therefore the current in the wire is 3.809A
<em>Note: The value obtained for the resistivity of Tungsten was theoretically obtained and can be consulted online.</em>
Answer:
Its ok but the answer is C
Explanation: