b The drift velocity does not depend on the length or the cross sectional area of the wire, when dealing with a macroscopic (ordinary, everyday life) wire. However, if the wire is, say, too short, e.g. comparable to the average distance a charge carrier travels before undergoing a collision, then it might begin to depend on the wire length, but for all practical intents and purposes a wire won't be that short.And we also know that,$v _{ d }=\frac{ I }{ eNA }$ where $I =$ current, $e =$ charge on electron, $N =$ no. of electrons,$A=$ area of cross-section.
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An ammeter $A$ of finite resistance, and a resistor $R$ are joined in series to an ideal cell $C$. $A$ potentiometer $P$ is joined in parallel to $R$. The ammeter reading is $I_0$ and the potentiometer reading is $V_0$. $P$ is now replaced by a voltmeter of finite resistance. The ammeter reading now is $I$ and the voltmeter reading is $V$.
In $a$ wire of cross-section radius $r$, free electrons travel with drift velocity $v$ when a current $I$ flows through the wire. What is the current in another wire of half the radius and of the same material when the drift velocity is $2v$?
In a large building, there are $15$ bulbs of $40\ W$, $5$ bulbs of $100\ W, 5$ fans of $80\ W$ and $1$ heater of $1\ kW$. The voltage of electric mains is $220\ V$. The minimum capacity of the main fuse of the building will be ................ $A$
In an electrical cable there is a single wire of radius $9\, mm$ of copper. Its resistance is $5\,\Omega $. The cable is replaced by $6$ different insulated copper wires, the radius of each wire is $3\,mm$. Now the total resistance of the cable will be ............... $\Omega$
A uniform metallic wire carries a current $2\,A$. when $3.4\,V$ battery is connected across it. The mass of uniform metallic wire is $8.92 \times 10^{-3} \,kg$. density is $8.92 \times 10^3\,kg / m ^3$ and resistivity is $1.7 \times 10^{-8} \Omega- m$. The length of wire is $l=............\,m$
In the circuit shown below, the cell has an $e.m.f.$ of $10\,V$ and internal resistance of $1\, ohm$. The other resistances are shown in the figure. The potential difference ${V_A} - {V_B}$ is ................ $V$