Assume a hypothetical wire in which free elec | vedclass

Name: Exam Paper Generator | JEE NEET Paper Generator | Vedclass
Brand: Vedclass
Rating: 5 (35 reviews)

Question

(A) The resistance $R$ of a wire is given by the formula $R = \frac{ho l}{A} = \frac{m l}{n e^2 	au A}$,where $m$ is the mass of an electron,$l$ is

Vedclass · Accepted Answer

Vedclass · Answer

(A) The resistance $R$ of a wire is given by the formula $R = \frac{ho l}{A} = \frac{m l}{n e^2 	au A}$,where $m$ is the mass of an electron,$l$ is the length,$A$ is the cross-sectional area,$e$ is the charge of an electron,$n$ is the free electron density,and $	au$ is the relaxation time.Given that $l$,$A$,$m$,$e$,and $	au$ are constant,the resistance $R$ is inversely proportional to the free electron density $n$,i.e.,$R \propto \frac{1}{n}$.It is given that $n \propto T$,therefore $R \propto \frac{1}{T}$.This relationship $R = \frac{k}{T}$ (where $k$ is a constant) represents a rectangular hyperbola,which corresponds to the graph shown in option $A$.

Assume a hypothetical wire in which free electron density changes with temperature in proportionality $n \propto T$,assuming $\tau$ (relaxation time of collision) and dimensions of the wire remain unchanged with increasing temperature. Which one of the resistance $v/s$ temperature graphs is true?

Similar Questions

An electric current flows along an insulated strip $PQ$ of a metallic conductor. The current density in the strip varies as shown in the graph. Which one of the following statements could explain this variation?

As shown in the figure,a current is passing through a conducting wire. The radius of the cross-section of the wire at point $A$ is $3r$ and at point $B$ is $r$. Find the ratio of the drift velocity at point $A$ to that at point $B$.

$A$ metal wire is subjected to a constant potential difference. When the temperature of the metal wire increases,the drift velocity of the electron in it

The mechanism of the heat produced in a conductor when an electric current flows through it can be explained on the basis of

$A$ copper wire of length $1 \ m$ and radius $1 \ mm$ is connected in series with an iron wire of length $2 \ m$ and radius $3 \ mm$. If a current flows through both wires,the ratio of the current density in the copper wire to that in the iron wire will be:

Vedclass Test Series

Exam Paper Generator

Online Exam Module