Problem 9: suppose you wanted to charge an initially uncharged 85 pf capacitor through a 75 mω resistor to 90.0% of its final voltage. randomized variables c = 85 pf r = 75 mω show answer no attempt how much time (in s) would be required to do this?

Explanation:

Given:

Capacitance, C = 85 pF = 85 × 10⁻¹² F

Resistance, R = 75 MΩ = 75×10⁶Ω

Charge in capacitor at any time 't' is given as:

where,

Q₀ = Maximum charge = CE

E = Initial voltage

t = time

also, Q = CV

V= Final voltage = 90% of E = 0.9E

thus, we have

or

or

taking log both sides, we get

or

or

or

neither accurate nor precise.