Question

1. assign a voltage value to each source in the circuits of figure 3 - 25 to obtain the indicated amounts of current.

Explanation:

Step1: Recall Ohm's law

$V = IR$

Step2: Calculate voltage for (a)

Given $I = 3\ mA=3\times10^{- 3}\ A$ and $R = 27\ k\Omega = 27\times10^{3}\ \Omega$. Then $V=(3\times10^{-3}\ A)\times(27\times10^{3}\ \Omega)=81\ V$

Step3: Calculate voltage for (b)

Given $I = 5\ \mu A = 5\times10^{-6}\ A$ and $R = 100\ M\Omega=100\times10^{6}\ \Omega$. Then $V=(5\times10^{-6}\ A)\times(100\times10^{6}\ \Omega)=500\ V$

Step4: Calculate voltage for (c)

Given $I = 25\ A$ and $R = 47\ \Omega$. Then $V=(25\ A)\times(47\ \Omega)=1175\ V$

Answer:

(a) $81\ V$; (b) $500\ V$; (c) $1175\ V$