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 beause

A :The drift velocity of electrons in a conductor is very small still current in a conductor is establised almost instantaneously on closing the switch. R: Electric field in the condutor sets up with speed of light.

STATEMENT-1 : The drift velocity of electrons in a metallic wire will decrease, if the temperature of the wire is increased. and STATEMENT-2 : On increasing the temperature of the wire , conductivity of metallic wire decreases.

The drift velocity of the electrons in a copper wire of length 2 m under the application of a potential difference of 220V is 0.5ms^-1 . Their mobility ( in m^2v^-1s^-1 )

Statement I: A wire of uniform cross-section and uniform resistivity is connected across an ideal cell. Now the length of the wire is doubled keeping volume of the wire constant. The drift velocity of electrons after stretching the wire becomes one-fouth of what it was before stretching the wire. Statement II: If a wire (of uniform resistivity and uniform cross section) of length l_0 is stretched to length nl_0 , then its resistance becomes n^2 times of what it was before stretching the wire (the volume of wire is kept constant in stretching process). Further at constant potential difference, current is inversely proportional to resistance. Finally, drift velocity of free electron is directly proportional to current and inversely proportional to cross-sectional area of current carrying wire.

Mobility of electrons in a semiconductor is defined as the ratio of their drift velocity to the applied electric field. If, for an n-type semiconuctor, the density of electrons is 10^(19)m^(-3) and their mobility is 1.6m^(2)//(V.s) then the resistivity of the semiconductor (since it is an n-type semiconductor contribution of holes is ignored) is close to :

(a). Consider circuit in figure. How much energy is absorbed by electrons from the initial state of no current (ignore thermal motion) to the state of drift velocity? (b). Electrons give up energy at the rate of RI^(2) per second to the thermal energy. what time scale would number associate with energy in problem (a)? n=number f electron/volume =10^(29)//m^(3) . Length of circuit =10cm , cross-section=A= (1mm)^(2) .

Consider the circuit in the figure. (a) how much energy is absorbed by electrons from the initial state of no current (ignore thermal motion) to the state of drift velocity? (b) Electrons give up energy at the rate of Rl^(2) per second to the thermal energy. What time scale would the number associate with energy in problem (a)? n = number of electron/volume =10^(29)//m^(3) . Length of circuit = 10cm cross-section = A = (1mm)^(2) .

A closed surface S is constructed around a conducting wire connected to a battery and a switch (figure 30-Q6). As the switch is closed, the free electrons in the wire start moving along the wire. In any time interval, the number of electrons entering the closed surface S is equal to the number of electrons leaving it. On closing the switch, the flux of the electric field through the closed surface

What is the drift velocity of electrons in a silver wire of length 2 m, having cross-sectional area 6.14xx10^(-6)m^(2) and carrying a current of 5A. Given, atomic weight of silver = 108, density of silver =9.5xx10^(3)kg//m^(3) , charge of electron =1.6xx10^(-19)C , Avogadro's number =6.023xx10^(26) per kmol?

A current i, indicated by the crosses in figure, is established in a strip of copper of height h and width w. A uniform field of magnetic induction B is applied at right angle to the strip. (a) Calculate the drift velocity v_d of the electrons. (b) What are the magnitude and direction of the magnetic force F acting on the electrons? (c) What should the magnitude and direction of a homogeneous electric field E be in order to counterbalance the effect of mangetic field? (d) Calculate voltage V necessary between two sides of the conductor in order to creat this field E Between which sides of the conductor would this voltage have to be applied? (e) If no electric field is applied from the outside, the electrons will be pushed somewhat to one side and therefore will give rise to a uniform electric field E_H across the conductor until the forces of this electrostatic field E_H balance the magnetic forces encountered in part (b). What will be the magnitude and direction of field E_H ? Assume that n, the number of conductor electrons per unit volume is 1.1xx10^(29) m^-3, h = 0.02 m, w= 0.1 cm, i = 50 A, and B=2 T.