Lesson 512 of 1524
Electric Current, Resistance, and Ohm's Law
The SI unit for current is the ampere (A), where 1 A = 1 C/s
Practice this chapterThe SI unit for current is the ampere (A), where 1 A = 1 C/s Electric current I is the rate at which charge flows, given by I = Δ Q Δ t , where Δ Q is the amount of charge passing through an area in time Δ t
The direction of conventional current is taken as the direction in which positive charge moves Drift velocity v d is the average speed at which these charges move
resistance — the electric property that impedes current; for ohmic materials, it is the ratio of voltage to current, R = V/I. electric current — the rate at which charge flows, I = Δ Q /Δ t. ohm — the unit of resistance, given by 1Ω = 1 V/A. drift velocity — the average velocity at which free charges flow in response to an electric field.
Worked example
What does “resistance” mean in Electric Current, Resistance, and Ohm's Law?
- 1Use the wording this chapter gives for resistance.
- 2The book says: the electric property that impedes current; for ohmic materials, it is the ratio of voltage to current, R = V/I.
- 3Do not use the meaning of electric current. That term means the rate at which charge flows, I = Δ Q /Δ t.
Result: the electric property that impedes current; for ohmic materials, it is the ratio of voltage to current, R = V/I
Why. That is the meaning this chapter gives for resistance.
Do not swap resistance and electric current. resistance means the electric property that impedes current; for ohmic materials, it is the ratio of voltage to current, R = V/I. electric current means the rate at which charge flows, I = Δ Q /Δ t.
Practice margin
This chapter
A fresh set from this chapter only. Choose 10 or 20. Multiple choice and fill-in, with no repeat inside the set.