Two wires each of radius of cross section r b | vedclass

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

Question

(C) The current $I$ flowing through a conductor is given by the formula $I = n e A V_{d}$,where $n$ is the charge carrier density,$e$ is the elementar

Vedclass · Accepted Answer

$4 : 1$

Vedclass · Answer

(C) The current $I$ flowing through a conductor is given by the formula $I = n e A V_{d}$,where $n$ is the charge carrier density,$e$ is the elementary charge,$A$ is the cross-sectional area,and $V_{d}$ is the drift velocity.Since the wires are connected in series,the current $I$ flowing through both wires must be the same.Given that both wires have the same radius $r$,their cross-sectional areas $A$ are also equal.Therefore,$n_{1} e A V_{d_{1}} = n_{2} e A V_{d_{2}}$.This simplifies to $n_{1} V_{d_{1}} = n_{2} V_{d_{2}}$,which implies $\frac{V_{d_{1}}}{V_{d_{2}}} = \frac{n_{2}}{n_{1}}$.Given the ratio of charge carrier densities is $\frac{n_{1}}{n_{2}} = \frac{1}{4}$,we have $\frac{n_{2}}{n_{1}} = \frac{4}{1}$.Thus,the ratio of drift velocities is $\frac{V_{d_{1}}}{V_{d_{2}}} = 4 : 1$.

Two wires each of radius of cross section $r$ but of different materials are connected together end to end (in series). If the densities of charge carriers in the two wires are in the ratio $1 : 4$,the drift velocity of electrons in the two wires will be in the ratio:

Similar Questions

The drift speed of electrons in a material is found to be $0.3 \ m s^{-1}$ when an electric field of $2 \ V m^{-1}$ is applied across it. The electron mobility (in $m^2 \ V^{-1} \ s^{-1}$) in the material is

$A$ current passes through a wire of nonuniform cross-section. Which of the following quantities are independent of the cross-section?

The relaxation time $\tau$ is nearly independent of the applied $E$ field,whereas it changes significantly with temperature $T$. The first fact is (in part) responsible for Ohm's law,whereas the second fact leads to the variation of resistivity $\rho$ with temperature. Elaborate why?

Assertion : The electric bulb glows immediately when the switch is on.
Reason : The drift velocity of electrons in a metallic wire is very high.

The potential difference across a conducting wire of length $20 \ cm$ is $30 \ V$. If the electron mobility is $2 \times 10^{-6} \ m^2 \ V^{-1} \ s^{-1}$,then the drift velocity of the electrons is

Vedclass Test Series

Exam Paper Generator

Online Exam Module