Capacitor charge time calculation - time constants

The video tutorial explains the charging and discharging process of a capacitor in a series circuit with a resistor and a switch. It introduces the concept of time constants, which are used to calculate the time it takes for a capacitor to charge to nearly full voltage. The tutorial provides a formula for calculating time constants and demonstrates how voltage levels change over time. It also covers the discharging process, showing how the voltage decreases exponentially. An example with a lamp and battery illustrates these concepts in a practical scenario.

What happens to the voltage across a capacitor when the switch in a series circuit is closed?

• It increases exponentially.

• It decreases linearly.

• It decreases exponentially.

• It remains constant.

How is the time constant of a circuit calculated?

• By dividing the resistance by the capacitance.

• By adding the resistance and capacitance.

• By multiplying the resistance by the capacitance.

• By subtracting the capacitance from the resistance.

If a resistor value is increased, what happens to the time constant?

• It increases.

• It remains the same.

• It becomes zero.

• It decreases.

At what percentage of the battery voltage is the capacitor charged after one time constant?

• 50%

• 100%

• 63.2%

• 75%

What is the voltage across the capacitor after 3 seconds if the time constant is 1 second?

• 9 volts

• 7.78 volts

• 8.55 volts

• 5.68 volts

During the discharging process, what is the voltage across the capacitor after one time constant?

• 63.2% of the initial voltage

• 50% of the initial voltage

• 36.8% of the initial voltage

• 0% of the initial voltage

How long will a lamp remain illuminated if connected to a discharging capacitor with a time constant of 1 second?

• Just under 1 second

• Just under 2 seconds

• Just under 3 seconds

• Just under 4 seconds