A prototype alarm circuit uses a capacitor that must reach of its final charge in no…

PHYSICS · Single correct · AP · Physics 2: Algebra-based · Electric Circuits · Electric Circuits

Problem

A prototype alarm circuit uses a

4.7\,\mu\text{F}

capacitor that must reach

90\%

of its final charge in no more than

25\,\text{ms}

. Resistors are limited to the following E12 series values:

1.0\,\text{k}\Omega

2.2\,\text{k}\Omega

3.3\,\text{k}\Omega

, and

4.7\,\text{k}\Omega

. Which resistor is the largest value that still meets the timing requirement? (a)

1.0\,\text{k}\Omega

(b)

4.7\,\text{k}\Omega

(c)

2.2\,\text{k}\Omega

(d)

3.3\,\text{k}\Omega