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Chapter 4: Q9DQ (page 840)

We have seen that a coulomb is an enormous amount of charge; it is virtually impossible to place a charge of 1 C on an object. Yet, a current of 10A,10C/sis quite reasonable. Explain this apparent discrepancy.

Short Answer

Expert verified

Current is the amount of charge flowing through a specified area, per unit of time.

So, it can be a very large amount of charge carriers with a very small charge that flows. Also, it can mean that a very small amount of charge flows through a specific area in a very short time.

Step by step solution

01

Definition.

Current is the amount of charge flowing through a specified area per unit time.

02

Explaining the apparent discrepancy.

This does not mean that it should be only one charge of 1 C flowing in one second.

It can be very large amount of charge carriers with a very small charge that flow.

This can be shown by equation 25.2, which is given by

I=nqvdA

Where, is the concentration of the charge carriers with charge q.

And in example 25.1, the free electron density in the wire is 8.5×1028m-3.

This amount of charge carriers are moving at a high speed vd,so it can cover a length of a wire in a very short time.

Also, it can mean that a very small charge flows through a specific area in a very short time.

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Most popular questions from this chapter

The energy that can be extracted from a storage battery is always less than the energy that goes into it while it is being charged. Why?

Copper has 8.5×1022free electrons per cubic meter. A 71.0-cm

length of 12-gauge copper wire that is 2.05 mm in diameter carries 4.85 A of

current. (a) How much time does it take for an electron to travel the length

of the wire? (b) Repeat part (a) for 6-gauge copper wire (diameter 4.12 mm)

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how does changing the diameter of a wire that carries a given amount of

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