{[ promptMessage ]}

Bookmark it

{[ promptMessage ]}

26_Ch 18 College Physics ProblemCH18 Direct-Current Circuits

26_Ch 18 College Physics ProblemCH18 Direct-Current...

Info iconThis preview shows page 1. Sign up to view the full content.

View Full Document Right Arrow Icon
124 CHAPTER 18 18.41 (a) The area of each surface of this axon membrane is ( ) ( ) ( ) 6 6 2 0.10 m 2 10 10 m 2 10 m A r π π π = = × = × A 2 and the capacitance is ( ) 6 2 12 2 2 0 -8 2 10 m 3.0 8.85 10 C N m 1.0 10 m A C d π κ × = = × × ( ) ( ) 8 1.67 10 F = × In the resting state, the charge on the outer surface of the membrane is ( ) 8 3 9 1.67 10 F 70 10 V 1.17 10 C 1.2 10 i i Q C V = = × × = × × 9 C The number of potassium ions required to produce this charge is 9 9 + -19 K 1.17 10 C 7.3 10 K ions 1.6 10 C i Q N e + × = = = × × and the charge per unit area on this surface is ( ) 9 2 -6 2 -19 1.17 10 C 1 10 m 2 10 m 1.6 10 C 1 Å i Q A σ π × = =  × × 0 2 2 2 4 2 1 1 8.6 10 Å 290 Å e e = = × 2 e This corresponds to a low charge density of one electronic charge per square of side 290 Å, compared to a normal atomic spacing of one atom per several Å
Background image of page 1
This is the end of the preview. Sign up to access the rest of the document.

{[ snackBarMessage ]}