A voltage source of 10.0 V is connected to a series RC circuit where R = 2.80 × 10 6 Ω, and C = 3.50 µF. Find the amount of time required for the current in the circuit to decay to 4.00% of its original value. Hint: This is the same amount of time for the capacitor to reach 96.0% of its maximum charge.

Respuesta :

Answer:

The amount of time is 31.45 sec.

Explanation:

Given that,

Voltage = 10.0 V

Resistance [tex]R=2.80\times10^{6}\ \Omega[/tex]

Capacitance [tex]C=3.50\ \mu F[/tex]

We need to calculate the time constant

Using formula of time constant

[tex]\tau=RC[/tex]

Put the value into the formula

[tex]\tau=2.80\times10^{6}\times3.50\times10^{-6}[/tex]

[tex]\tau=9.8\ sec[/tex]

The amount of time required for the current in the circuit to decay to 4.00% of its original value.

We need to calculate the amount of time

Using formula of charge

[tex]Q=Q_{max}(1-e^{\dfrac{-t}{RC}})[/tex]

Put the value into the formula

[tex]96\%Q_{max}=Q_{max}(1-e^{\dfrac{-t}{RC}})[/tex]

[tex]0.96=(1-e^{\dfrac{-t}{\tau}})[/tex]

[tex]0.96=(1-e^{\dfrac{-t}{\tau}})[/tex]

[tex]0.04=e^{\dfrac{t}{\tau}}[/tex]

[tex]\dfrac{-t}{\tau}=ln(0.04)[/tex]

[tex]t=3.21\times9.8[/tex]

[tex]t=31.45\ sec[/tex]

Hence, The amount of time is 31.45 sec.