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Assertion: Drift velocity of electrons i...

Assertion: Drift velocity of electrons is independent of time.
Reason: Electrons are accelerated in the presence of electric field.

A

If both assertion and reason are true and reason is the correct explantion of assertion.

B

If both assertion and reason are true and reason is not the correct explantion of assertion.

C

If assertion is false but reason is true.

D

If assertion is true but reason is false.

Text Solution

Verified by Experts

The correct Answer is:
B
Drift velocity is the average velocity of electrons in presence of electric field, which is independent of time.
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State the direction of drift velocity of electron with respect to the appliled electric field.

Define drift velocity of free electron . If relaxation time is r then write a vector relation b etween drift velocity and electric field.

Knowledge Check

  • The drift velocity of electrons is given by

    A
    `v_(d)=(e)/(m)(V)/(l)t`
    B
    `v_(d)=(eV t)/(l)`
    C
    `v_(d)=(e)/(m)t`
    D
    `v_(d)=(V)/(l)(m)/(e)t`

  • The average velocity of electrons in a conductor in the absence of electric field is

    A
    `10^(2)`m/s
    B
    `10^(-2)`m/s
    C
    `10^(4)` m/s
    D
    `10^(-4)` m/s

  • Assertion (A): There is no current in the metals in the absence of an electric field. Reason (R) : Motion of free electrons are randomly directed in the absence of an electric field.

    A
    If both assertion and reason are true and the reason is the correct explanation of the assertion.
    B
    If both assertion and reason are true but reason is not the correct explanation of the assertion.
    C
    If assertion is true but reason is false.
    D
    If the assertion is false but reason is true.

    • Similar Questions

    Explore conceptually related problems

    The drift velocity of free electrons in metals is of the order of_______.

    Assertion: Through large number of free electron are present in the metal, yet there is no current in the absent of electric field. Reason: In the absence of electric field, electrons move remdomly in all directions

    Assertion : The drift velocity of electrons in a metallic wire will decrease, if the temperature of the wire is increased. Reason : On increasing temperature, conductivity of metallic wire decreases.

    Assertion : The drift velocity of electrons in a metallic wire will decrease, if the temperature of the wire is increased. Reason : On increasing temperature, conductivity of metallic wire decreases.

    Assertion: Drift velocity of electrons developed in a current-carrying conductor is of the order of 10^(-4) m//s but current in the conductor is established almost instantly the switch is closed. Reason: Electric field in a conductor sets up with the speed of light.

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