Question

The circuit shown below uses a neon-filled tube in the setup below. The neon lamp has a threshold voltage V₀ for conduction, because no current flows until the neon gas in the tube is ionized by a sufficiently strong electric field. Once the threshold voltage is exceeded, the lamp has negligible resistance.
The capacitor stores electrical energy, which can be released to flash the lamp. Assume that C = 6.10

Answer 1

a)

You will have to show or describe the circuit to be certain. I will assume that 110 V is connected to R and C in series and that the neon bulb is in parallel with C.

The voltage across a discharged capacitor is 0 at t=0 and grows to the applied voltage over time. (In engineering, 5*RC is usually considered charged.)

Vc=emf(e^(-t/RC))

84 = 110 * e^-t/RC = 110 e^-t/(2.77*10^6*6.1*10^-8)

t = 0.4556 s

(iii) The capacitor charges for half the time it charged initially and repeats