Hugh D. Young, Roger A. Freedman

Physics

14th edition Edition 路 1596 pages

ISBN: 9780321973610

Chapter 4: Q28E (page 1014)

In Fig. $30.11, suppose that 蔚 = 60 V, R = 240 惟, and L = 0.16 H .$ . Initially there is no current in the circuit. Switch $S 2$ is left open, and switch $S 1$ is closed. (a) Just after role="math" localid="1664197497741" $S 1$ is closed, what are the potential differences $v_{a b} a n d v_{b c}$ ? (b) A long time (many time constants) after $S 1$ is closed, what are $v_{ab} a n d v_{bc}$ ? (c) What are $v_{ab} a n d v_{bc}$ at an intermediate time when $i = 0.15 A$ ?

Expert verified

$(a) 0, 60 V (b) 0, 60 V (c) 36 V, 24 V$

Step by step solution

Recall that for $V_{a b}$ this potential grows in a logarithmic manner and is zero initially.

role="math" localid="1664198040104" $v_{a b} = 0 v_{b c} = L \frac{d i}{d t} v_{b c} = L \frac{蔚}{L} v_{b} c = 蔚 v_{b} c = 60 V$

As $t 鈫� 鈭�, i 鈫� \frac{蔚}{R}$ and $\frac{d i}{d t} 鈫� 0$

$v_{b} c = 0 v_{a} b = i R v_{a} b = R \frac{蔚}{R} v_{a} b = 蔚 v_{a} b = 60 V$

We are now investigating at a time between $t_{i n i t i a l}$ and $t_{f i n a l}$ such that neither term is zero.

$v_{a} b = i R = 0.15 脳 240 = 36 V v_{b} c = 蔚 - v_{a} b v_{b} c = 24 V$

Unlock Step-by-Step Solutions & Ace Your Exams!

Over 30 million students worldwide already upgrade their learning with 91影视!

All the tools & learning materials you need for study success - in one app.

Recommended explanations on Physics Textbooks

View all explanations

What do you think about this solution?

We value your feedback to improve our textbook solutions.