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प्रश्न
How does drift velocity of electrons in a metallic conductor vary with increase in temperature? Explain.
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उत्तर
Drift velocity of electrons in a metallic conductor decreases with increase in temperature.
As we know,
As, we increase the temperature of the metallic conductor the collision between the electrons and ions increases, which results in the decrease in the relaxation time. so, from the equation (4)
vd ∝ r
Hence, the drift velocity decreased.
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संबंधित प्रश्न
Estimate the average drift speed of conduction electrons in a copper wire of cross-sectional area 2.5 × 10−7 m2 carrying a current of 1.8 A. Assume the density of conduction electrons to be 9 × 1028 m−3.
A conductor of length ‘l’ is connected to a dc source of potential ‘V’. If the length of the conductor is tripled by gradually stretching it, keeping ‘V’ constant, how will (i) drift speed of electrons and (ii) resistance of the conductor be affected? Justify your answer.
Derive an expression for drift velocity of free electrons in a conductor in terms of relaxation time.
Obtain the expression for the current flowing through a conductor having number density of the electron n, area of cross-section A in terms of the drift velocity vd .
Metals are good conductor of heat than insulator because
The relaxation time τ is nearly independent of applied E field whereas it changes significantly with temperature T. First fact is (in part) responsible for Ohm’s law whereas the second fact leads to variation of ρ with temperature. Elaborate why?
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.
What is the average time interval between two successive collisions of a free electron with the ions of the metallic lattice called?
When an electric field \[E\] is applied to a conductor, what force direction does an electron of charge \[-e\] experience?
If \[n\] is the number of free electrons per unit volume and \[A\] is the conductor’s cross-sectional area, which expression gives the current from electron drift?
