A current I is passing through a wire having | vedclass

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

Question

(C) The drift velocity $v_d$ of electrons in a conductor is given by the formula $v_d = \frac{I}{neA}$,where $I$ is the current,$n$ is the number dens

Vedclass · Accepted Answer

$v_P = \frac{1}{4}v_Q$

Vedclass · Answer

(C) The drift velocity $v_d$ of electrons in a conductor is given by the formula $v_d = \frac{I}{neA}$,where $I$ is the current,$n$ is the number density of electrons,$e$ is the charge of an electron,and $A$ is the cross-sectional area.Since $I$,$n$,and $e$ are constant for both sections,we have $v_d \propto \frac{1}{A}$.The area of cross-section $A$ is given by $A = \pi r^2 = \pi (d/2)^2 = \frac{\pi d^2}{4}$,which implies $A \propto d^2$.Therefore,$v_d \propto \frac{1}{d^2}$.For sections $P$ and $Q$,we have $\frac{v_P}{v_Q} = \left( \frac{d_Q}{d_P} \right)^2$.Given $d_P = d$ and $d_Q = d/2$,we get $\frac{v_P}{v_Q} = \left( \frac{d/2}{d} \right)^2 = \left( \frac{1}{2} \right)^2 = \frac{1}{4}$.Thus,$v_P = \frac{1}{4}v_Q$.

$A$ current $I$ is passing through a wire having two sections $P$ and $Q$ of uniform diameters $d$ and $d/2$ respectively. If the mean drift velocity of electrons in sections $P$ and $Q$ is denoted by $v_P$ and $v_Q$ respectively,then

Similar Questions

The dimensional formula of mobility is . . . . . .

When $5\ V$ potential difference is applied across a wire of length $0.1\ m$,the drift speed of electrons is $2.5 \times 10^{-4} \ m/s$. If the electron density in the wire is $8 \times 10^{28} \ m^{-3}$,the resistivity of the material is close to:

The unit of mobility in terms of fundamental units is . . . . . . .

$A$ wire has a non-uniform cross-section as shown in the figure. $A$ steady current flows through it. The drift speed of electrons at points $P$ and $Q$ is $v_P$ and $v_Q$ respectively.

$A$ cylindrical wire of radius $0.5 \, mm$ and conductivity $5 \times 10^{7} \, S/m$ is subjected to an electric field of $10 \, mV/m$. The expected value of current in the wire will be $x^{3} \, \pi \, mA$. The value of $x$ is ......

Vedclass Test Series

Exam Paper Generator

Online Exam Module