Pre Quiz Capacitor (Take Home Quiz)

Which of the following do not affect capacitance of a capacitor?

• Area of the plates

• Separation of the plates

• Material between the plates

• Charge on the plates

A battery establishes a voltage V on a parallel-plate capacitor. After the battery is disconnected, the distance between the plates is doubled without loss of charge. Accordingly, the capacitance _________ and the voltage between the plates _________.

• increases; decreases

• decreases; increases

• increases; increases

• decreases; decreases

A capacitor discharges through a resistor. The time constant of the circuit is 5 s. What is the time taken, in s, for the charge on the plates of the capacitor to halve?

• 0.5 ln2

• 0.5 ln5

• 2 ln5

• 5 ln2

There is a potential difference of 6 V across a 220 μF capacitor. The charge stored on the capacitor is....

• 0.00132 C

• 27272 C

• 0.000037 C

• 226 C

When the potential difference across a capacitor is V, the energy stored by the capacitor is W. Which of the following gives the energy stored by the capacitor when the potential difference across the capacitor is 2V?

• W

• 2W

• 3W

• 4W

Which one is the function of capacitor?

• Semiconductor device used to amplify or switch electrical signals and power

• Device used to limit or regulates the flow of electrical current

• Device used to store charge

• Device used to convert from alternating current to direct current

An uncharged capacitor is connected in series with a battery and a resistor. Which of the following graphs shows the variation of current I with time t as the capacitor charges?

• A

• B

• C

• D

A 4.0 μF capacitor discharges through a 560 kΩ resistor. What is the time needed for the capacitor to discharge to 37% from its maximum capacity?

• 2.2 s

• 0.0022 s

• 0.45 s

• 450 s

Two capacitors X and Y of capacitances 2 F and 4 F respectively are connected in series with

a 12 V battery. Which of the following statements is correct?

• The effective capacitance is 6 F.

• Capacitors have the same charge of 36 C.

• The potential difference across the capacitor X is 8 V.

• The potential difference across the capacitors Y is 12 V.

Which of the following statements does not describe a capacitor an electrical device?

• A. It stores charge and electrical potential energy.

• B. It is manufactured in many sizes and shapes.

• C. It is used to smooth out unwanted fluctuations due to power surges in electronic circuits.

• D. It allows current to pass through in any condition.