Two copper wires of equal length but different thickness are connected one by one to the same cell and bulb.
(a) In which wire will the rate of flow of the charge be greater? Give reason.
(b) Does a higher current mean that electrons move faster from the battery to the bulb?
(c) If current flows for a longer time, what happens to the charge passing per second? What happens to the total charge transferred?

Question

Two copper wires of equal length but different thickness are connected one by one to the same cell and bulb.
(a) In which wire will the rate of flow of the charge be greater? Give reason.
(b) Does a higher current mean that electrons move faster from the battery to the bulb?
(c) If current flows for a longer time, what happens to the charge passing per second? What happens to the total charge transferred?

KnowledgeBoat · Accepted Answer

(a) The thicker wire will have a greater rate of flow of charge (higher current) because a thicker wire has a larger cross-sectional area, offering less resistance, so more charge can pass per second.

(b) No, not necessarily.
Current is the amount of charge flowing per second:

$I = \dfrac{Q}{t}$

So, a higher current means that more charge passes through the wire per second. It does not simply mean that electrons travel faster from the battery to the bulb.

(c) Charge flowing through a wire is given by,

$\text {Charge} = \text {Current flowing} \times \text {Time taken}$

So if current flows for a longer time, the charge passing per second (current) remains the same (assuming constant conditions), however, the total charge transferred increases with time.

Physics

Current Electricity

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