Question

The timing device in an automobile's intermittent wiper system is based on an RC time constant and utilizes a 25.0 µF capacitor and a variable resistor. Over what range must R be made to vary to achieve time constants from 2.00 to 15.0 s?

a) 1.33 × 10Ω
b) 1.78 × 1052
c) 2.22 × 1042
d) 2.67 × 102

Answer 1

The resistance R must vary over the range of 0.08 × 10^6 Ω to 0.6 × 10^6 Ω to achieve time constants from 2.00 to 15.0 s in the automobile's intermittent wiper system.

Step-by-step explanation:

The timing device in an automobile's intermittent wiper system is based on an RC time constant. The time constant, denoted by the symbol T, is given by the equation T = RC, where R is the resistance and C is the capacitance. To achieve time constants from 2.00 to 15.0 s, we can rearrange the equation to solve for R: R = T/C. Therefore, R must vary over the range of 2.00 s/25.0 µF to 15.0 s/25.0 µF.