There is a current of 1.344 amp in a copper wire whose area...

There is a current of $1.344$ amp in a copper wire whose area of cross-section normal to the length of the wire is $1 \mathrm{~mm}^{2}$. If the number of free electrons per $\mathrm{cm}^{3}$ is $8.4 \times 10^{22}$, then the drift velocity would be (a) $1.0 \mathrm{~mm} / \mathrm{s}$ (b) $1.0 \mathrm{~m} / \mathrm{s}$ (c) $0.1 \mathrm{~mm} / \mathrm{s}$ (d) $0.01 \mathrm{~mm} / \mathrm{s}$

There is a current of $1.344$ amp in a copper wire whose area of cross-section normal to the length of the wire is $1 \mathrm{~mm}^{2}$. If the number of free electrons per $\mathrm{cm}^{3}$ is $8.4 \times 10^{22}$, then the drift velocity would be
(a) $1.0 \mathrm{~mm} / \mathrm{s}$
(b) $1.0 \mathrm{~m} / \mathrm{s}$
(c) $0.1 \mathrm{~mm} / \mathrm{s}$
(d) $0.01 \mathrm{~mm} / \mathrm{s}$

Key Concepts

Cross-sectional Area

The cross-sectional area of a conductor is the area through which charge carriers move. It plays a key role in current calculations because it affects the current density, which is the current per unit area, and thus influences drift velocity.

Charge Carrier Density

Charge carrier density refers to the number of free charge carriers (such as electrons) per unit volume in a material. This concept is crucial in determining how easily a material can conduct electricity, as a higher density of carriers generally leads to better conductivity.

Elementary Charge

The elementary charge is the basic unit of electric charge carried by a single proton or, with opposite sign, by a single electron. It is a critical constant in calculations involving electric currents and drift velocity since it quantifies the amount of charge each carrier moves.

Current

Current is the rate at which electric charge flows through a conductor. It is a fundamental concept in electricity and is measured in amperes. In conductive materials, current arises from the movement of charge carriers, typically electrons.

Drift Velocity

Drift velocity is the average velocity that charge carriers, like electrons, attain when subjected to an electric field within a conductor. It is determined by the relationship between the current, the number density of the carriers, the charge carried by each carrier, and the conductor's cross-sectional area.

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