BackLightning occurs when there is a flow of electric charge (principally electrons) between the ground and a thundercloud. The maximum rate of charge flow in a lightning bolt is about C/s; this lasts for ms or less. How much charge flows between the ground and the cloud in this time? How many electrons flow during this time?
A hollow copper wire with an inner diameter of 1.0 mm and an outer diameter of 2.0 mm carries a current of 10 A. What is the current density in the wire?
A car battery is rated at 90 A h, meaning that it can supply a 90 A current for 1 h before being completely discharged. If you leave your headlights on until the battery is completely dead, how much charge leaves the battery?
For the wire in Fig. 25–38, whose diameter varies uniformly from a to b as shown, suppose a current I = 2.5 A enters at a. If a = 2.5 mm and b = 4.0 mm, what is the current density (assume uniform) at each end?
(II) What is the current in amperes if 1200 Na⁺ ions flow across a cell membrane in 2.8 μs? The charge on the sodium is the same as on an electron, but positive.
What diameter should the nichrome wire in FIGURE P27.62 be in order for the electric field strength to be the same in both wires?
The biochemistry that takes place inside cells depends on various elements, such as sodium, potassium, and calcium, that are dissolved in water as ions. These ions enter cells through narrow pores in the cell membrane known as ion channels. Each ion channel, which is formed from a specialized protein molecule, is selective for one type of ion. Measurements with microelectrodes have shown that a 0.30-nm-diameter potassium ion (K+) channel carries a current of 1.8 pA. How many potassium ions pass through if the ion channel opens for 1.0 ms?
(I) A current of 1.75 A flows in a wire. How many electrons are flowing past any point in the wire per second?