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प्रश्न
(a) drift speed
(b) current density
(c) electric current
(d) electric field
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उत्तर
The electric current will remain constant in a wire whose cross-sectional area is increasing linearly from its one end to the other, is connected across a battery of V volts.
Because current is the only quantity that does not depend on the area of cross- sections of the wire.
`I=(dq)/(dt)`, that is the rate of flow of charge, where as drift speed, current density and electric field are depends on the increasing area of cross-section with the following relations:
Drift speed: `ν_d=I/(An""e)`
Current density = `I/A`
Electric field = `J/σ`
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संबंधित प्रश्न
Define the term drift velocity.
Write its (‘mobility’ of charge carriers) S.I. unit
Estimate the average drift speed of conduction electrons in a copper wire of cross-sectional area 1.0 × 10−7 m2 carrying a current of 1.5 A. Assume the density of conduction electrons to be 9 × 1028 m−3
Consider the following statements.
(A) Free-electron density is different in different metals.
(B) Free-electron density in a metal depends on temperature.
Thomson Effect is caused _______________ .
Amount of charge in coulomb required to deposit one gram equivalent of substance by electrolysis is:-
Is the momentum conserved when charge crosses a junction in an electric circuit? Why or why not?
The potential difference applied across a given conductor is doubled. How will this affect (i) the mobility of electrons and (ii) the current density in the conductor? Justify your answers.
The drift velocity of electrons in a conductor connected to a battery is given by vd = `(−"eE" τ)/"m"`. Here, e is the charge of the electron, E is the electric field, τ is the average time between collisions and m is the mass of the electron.
Based on this, answer the following:
- How does the drift velocity change with a change in the potential difference across the conductor?
- A copper wire of length 'l' is connected to a source. If the copper wire is replaced by another copper wire of the same area of cross-section but of length '4l', how will the drift velocity change? Explain your answer.
What is the average velocity of electrons when no electric field is present?
Which expression gives the acceleration of an electron in an electric field?
