Drift velocity and mobility - class-XI
| Description: drift velocity and mobility | |
| Number of Questions: 52 | |
| Created by: Priya Bakshi | |
| Tags: current electricity electric current electric current through conductors electric current, potential difference and resistance physics |
A charged particle having drift velocity of $7.5\times 10^{-4}m$ $s^{-1}$ in electric field of $3\times 10^{-10}$V $m^{-1}$, mobility is?
Which of the following characteristics of electrons determines the current in a conductor?
When current flows through a conductor, then the order of drift velocity of electrons will be:-
Potential difference of $100 V$ is applied to the ends of a copper wire one metre long. Find the ratio of average drift velocity and thermal velocity of electrons at $27^\circ C$. (Consider there is one conduction electron per atom. The density of copper is $9.0 \times 10^3$; Atomic mass of copper is $63.5 g$.
$N _A = 6.0 \times 10^{23}$ per gram-mole, conductivity of copper is $5.81 \times 10^{7} \Omega^{-1}$.$K =1.38 \times 10^{-23} JK^{-1}$).
Assertion: When a straight wire is bent to form L-shape, its resistance increases.
Reason: Electrons take longer time to travel along a bent wire, as compared to travel along a straight wire.
When the current in a wire is 1A, the drift velocity is $1.2\times 10^{-4}ms^{-1}$. The drift velocity when current becomes 5 A is
A charge $A$ of $+3 \ mC$ is placed at $k=0$ and a charge $B$ of $-5 \ mC$ at $k=40 \ mm.$ Where a third charge q be placed on the axis such that it experiences no force is
In conducting wire of radius $5 \, mm$, resistivity $\rho = 1.1 \times 10^{-8} \Omega/m$ and current of $5 A$ is flowing. Drift velocity of free electron is $1.1 \times 10^{-3} \, m/s$ find out mobility of free electron.
A current passes through a resistor. If K$ _1$ and K$ _2$ represent the average kinetic energy of the conduction electrons and the metal ions respectively then
Mobility of free electrons in a conductor is:
A 2-ampere current flows in a conductor which has $1 \times {10^{24}}$ free electrons per meter. What is their average drift velocity?
An electric current of $16A$ exists in a metal wire of cross section ${ 10 }^{ -6 }{ m }^{ 2 }$ and length $1m$. Assuming one free electron per atom. The drift speed of the free electrons in the wire will be:
(Density of metal $=5\times { 10 }^{ }kg/{ m }^{ 3 }$, atomic weight $=60$)
Drift velocity $v _a$ varies with the intensity of elastic filed as per the relation:
A copper wire of cross-section $2\ {mm}^{2}$ carries a current of $30\ A$. Calculate the root mean square velocity (thermal velocity) of free electrons at $27^oC$. Also ${v} _{d}$ is very small compared to it.
[Data given: ${ \rho } _{ { C } _{ 0 } }=8.9\ gm/cc$, Boltzmann constant $(k)=1.38\times {10}^{23}J/K$
${m} _{0}=9.1\times {10}^{-31}kg.{N} _{A}=6.023\times {10}^{23}$ atomic weight of $Cu=63$]
Two wires $X$ and $Y$ have the same resistivity but their cross-sectional areas are in the ratio $2 : 3$ and lengths in the ratio $1 : 2$. They are first connected in series and then the parallel to a d.c. source. Find the ratio of their drift speeds of the electrons in the two wires for the two cases.
The drift velocity of the electron in a copper wire of length 2m under the application of a potential difference of 200 V is $0.5 ms^{-1}$.Their mobility is (in $m^{-2} V^{-1} s^{-1}$)
Current is flowing with a current density $J=480\ amp/cm^{2}$ in a copper wire. Assuming that each copper atom contribution one free electron and gives that Avogadro number$=6.0\times 10^{23}\ atoms/mole$ Density of copper $=9.0\ g/cm^{3}$ .Atomic weight of copper $=64\ g/mole$ Electronic charge $=1.6\times 10^{-19}$ coulomb. The drift velocity of electrons is:
Assume that each atom of copper contributes one free electron. The density of copper is $9g cm^{-3}$ and atomic weight of copper is $63$. If the current flowing through a copper wire of $1mm$ diameter is $1.1 $ ampere, the drift velocity of electrons will be:-
Find the time an electron takes to drift from one end of a uniform wire $3m$ long to its other end if the wire is $2$ x ${ 10 }^{ -6 }{ m }^{ 2 }$ in cross section and carries a current $3A$.The density of free electrons in a copper conductor is $8.5$ x ${ 10 }^{ 28 }{ m }^{ 3 }$.
How many electrons should be removed from a coil of mass 1.6 gram so that it may float in an electric field of intensity $10^9 NC^-1$ directed upwards ?
How many electrons should be removed from a coin of mass 1.6 gram, so that it may float in an electric field of intensity $10^9 NC^-1$ directed upwards?
A current of $1.0A$ exists in a copper wire of cross-section $1.0mm^2$.Assuming one free electron per atom
There is a current of 1.344 amp in a copper wire whose area of cross-section normal to the length of the wire is $ 1 mm^2 $. If the number of free electrons per $ cm^3 is 8.4 \times 10^22 $, then the drift velocity would be
A current I flows through a uniform wire of diameter d when the electron drift velocity is V .The same current will flow through a wire of diameter d/2 made of the same material if the drift velocity of the electrons is
There is a current of 40 amperes in a wire of $10^{-16}m^{2}$ area of cross-section. If the number of free electrons per $m^{3}$ is $10^{29}$, then the drift velocity will be:
A potential difference $V$ is applied to a copper wire of length $l$ and thickness $d$. If $V$ is doubled, the drift velocity:
The number of free electrons per $10$ mm ordinary copper wire is about $2\times 10^{21}$. The average drift speed of the electrons is $0.25$ mm current flowing is:
There is current of 40 amperes in a wire of $10^{-6}m^{2}$ area of cross -section. If the number of free electrons per $m^{3}$ is $10^{29}$, then the drift velocity will be
Drift speed of conduction electrons in the wire is
In a wire of cross section radius r, free electrons travel with drift velocity V when a current a $I$ flows throught the wire. What is the current in another wire of half the radius and of the same material when the drift velocity is $2V$ ?
Which of the following quantities do not change when an ohmic resistor connected to a battery is heated due to the current?
The drift of the electrons in a copper-wire of length 2 m under the application of potential difference of $ 200 V is 0.5 ms^{-1} $ . their mobility is $ (inm^2V^{-1}s^{-1} ) $
In semiconductor the concentrations of electrons and holes are $8 \times 10 ^ { 18 } / \mathrm { m } ^ { 3 }$and $5 \times 10 ^ { 8 } / \mathrm { m } ^ { 3 }$ respectively.If the mobilities of electrons and holes are 2.3$\mathrm { m } ^ { 2 } / \mathrm { Vs }$ and 0.01$\mathrm { m } ^ { 2 } / \mathrm { Vs }$ respectively then semi conductor is
The mean free path of electrons in a metal is $44 \times 10 ^ { - 8 } \mathrm { m }$ . Theelectric field which can give on an average 2$e \mathrm { V }$ energy to an electron in the metal will be in units of VIm
When 3 V potential difference is applied a wire of length 0.1 m. having resistivity $1.6 \times 10^{-5}$ $\Omega m$, the electrons started moving. If the electron density in the wire is $6 \times 10^{10} m^{-1}$, the drift speed of electrons is
The drift velocity of free electron in a metal wire of a given potential gradient along it is $ V _d $ if this potential gradient is doubled the new drift velocity will be
Unit of mobility :
When a potential difference $V $ is applied across a conductor at a temperature $T,$ the drift velocity of electrons is proportional to
If temperature is decreased, then relaxation time of electrons in metals will
A potential difference V is applied across a copper wire of diameter d and length L. when only d is doubled, the drift velocity :-
The drift velocity of electrons in a conducting wire is of the order of $1:mm/s$, yet the bulb glows very quickly after the switch is put on because
A potential difference v exists between the ends of a metal wire of length l. The drift velocity will be doubled if
Assertion : A current flows in a conductor only when there is an electric field within the conductor.
Reason : The drift velocity of electron in presence of electric field decreases.
The electron drift speed is small and the charge of the electron is also small but still, we obtain large current in a conductor. This is due to
Two wires, each of radius r, but of different materials are connected together end to end. If the densities of charge carriers in the two wires are in the ratio 1:4, the ratio of the drift velocity of electrons in the two wires will be . .
The drift velocity of an electron is doubled if the applied electric field across the conductor is .....
When there is an electric current through a conducting wire along its length then an electric field must exist
Copper contains $8.4\times 10^{28}$ free electrons$/m^3$. A copper wire of cross-sectional area $7.4\times 10^{-7}m^2$ carries a current of $1$A. The electron drift speed is approximately.
Drift velocity varies with the intensity of electric field as per the relation
a current 10 ampere is maintained in a conductor of cross section of $ 10^{-4}m^2 $. if the electron density is $ 9 \times 10^{28} m^{-3} $ , what is the drift velocity of free electrons?
The relaxation time $(t)$ is the:
The drift velocity of free electrons in a conductor is $v$, when a current. $I$ is flowing in it if both the radius and current are doubled, then drift velocity will be.