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Lesson: Capacitor Charging and Discharging

Worksheet: Capacitor Charging and Discharging • 11 Questions


A 500- resistor, an uncharged 1.50- capacitor, and a 6.16-V emf are connected in series.

What is the initial current?

What is the time constant?

  • A s
  • B s
  • C s
  • D s
  • E s

What is the current after one time constant?

What is the voltage on the capacitor after one time constant?


The timing device in an automobile’s intermittent wiper system is based on an time constant and utilizes a 0.500-μF capacitor and a variable resistor. Over what range must be made to vary to achieve time constants from 2.00 to 15.0 s?

  • A4.33 to 30.0 MΩ
  • B3.33 to 33.3 MΩ
  • C4.00 to 30.0 MΩ
  • D4.00 to 40.0 MΩ
  • E3.00 to 30.0 MΩ


If you wish to take a picture of a bullet traveling at 500 m/s, then a very brief flash of light produced by an discharge through a flash tube can limit blurring. Assuming 1.00 mm of motion during one constant is acceptable, and given that the flash is driven by a 600- capacitor, what is the resistance in the flash tube?

  • A Ω
  • B Ω
  • C Ω
  • D Ω
  • E Ω


The duration of a photographic flash is related to an time constant, which is 0.100 µs for a certain camera. The capacitor in the camera is in a circuit with a charging resistance of 800 kΩ, while the flash lamp of the camera has a resistance of 40.0 mΩ during discharge.

What is the capacitance of the capacitor?

What is the time constant for charging the capacitor?


A circuit contains a 160-μF capacitor charged to 450 V. The circuit is discharged through a 31.2-kΩ resistor.

Find the time constant of the circuit.

Calculate the temperature increase of the resistor, given that its mass is 2.50 g and its specific heat capacity is . Assume that all of the thermal energy resulting from the discharge is retained in the short time that the discharge lasts.