Current and Drift Velocity Relation

Q.

An air capacitor of capacity $c=10\mu f$ is connected to a constant voltage battery of $12V$. Now the space between the plates is filled with a liquid of dielectric constant $5$. The (additional) charge that flows now from the battery to the capacitor is:

1. $480\mu C$

2. $120\mu C$

3. $240\mu C$

4. $600\mu C$

Q. A current passes through a wire of nonuniform cross-section. Which of the following quantities is independent of the cross-section?

1. The charge crossing in a given time interval.
2. Drift speed
3. Current density
4. None of these

Q. A conducting wire of cross-sectional area $1c{m}^2$ has $3\times {10}^{23}$ number of charge carriers per unit volume. If wire carries a current of $24mA$, the drift speed of the carrier is ___________.

1. $5\times {10}^{-6}m{s}^{-1}$
2. $5\times {10}^{-3}m{s}^{-1}$
3. $0.5m{s}^{-1}$
4. $5\times {10}^{-2}m{s}^{-1}$

Q. We know that current $I=neA{V}_d$ where $V_d$ is the drift speed, A is the cross sectional area, e is the magnitude of charge on an electron and n is the number of free charge carriers in unit volume of a conductor. In a conductor of non-uniform cross-sectional area as shown

1: The current at P will be more than the current at Q
2: Because current is directly proportional to cross-sectional area so current increases as the cross sectional area increases

1. Statement 1 is correct, Statement 2 is the correct and Statement 2 is the correct explanation for statement 1
2. Statement 1 is correct, Statement 2 is the correct and Statement 2 is not the correct explanation of statement 1
3. Statement 1 is correct but Statement 2 is wrong
4. Both statements are wrong

Q. A conducting wire of cross-sectional area $1c{m}^2$ has $3\times {10}^{23}$ number of charge carriers per unit volume. If wire carries a current of $24mA$, the drift speed of the carrier is ___________.

1. $5\times {10}^{-6}m{s}^{-1}$
2. $5\times {10}^{-3}m{s}^{-1}$
3. $0.5m{s}^{-1}$
4. $5\times {10}^{-2}m{s}^{-1}$

Q. If the drift velocity of electrons in a conductor is V, then the drift velocity in another conductor of same material, but double the cross section and carrying half the current of first conductor is.

1. $V$
2. $\frac{V}{4}$
3. $\frac{V}{3}$
4. $\frac{V}{6}$