Deck 9: Capacitance

Question 1

The units of capacitance are equivalent to:

A) J/C
B) V/C
C) J²/C
D) C/J
E) C²/J

Answer 1

C²/J

Question 2

A farad is the same as a:

A) J/V
B) V/J
C) C/V
D) V/C
E) N/C

Answer 2

C/V

Question 3

To charge a 1-F capacitor with 2 C requires a potential difference of:

A) 2 V
B) 0.2 V
C) 5 V
D) 0.5 V
E) none of these

Answer 3

2 V

Question 4

The capacitance of a parallel-plate capacitor can be increased by:

A) increasing the charge
B) decreasing the charge
C) increasing the plate separation
D) decreasing the plate separation
E) decreasing the plate area

Question 5

If both the plate area and the plate separation of a parallel-plate capacitor are doubled, the capacitance is:

A) doubled
B) halved
C) unchanged
D) tripled
E) quadrupled

Question 6

Pulling the plates of an isolated charged capacitor apart:

A) increases the capacitance
B) increases the potential difference
C) does not affect the potential difference
D) decreases the potential difference
E) does not affect the capacitance

Question 7

If the charge on a parallel-plate capacitor is doubled:

A) the capacitance is halved
B) the capacitance is doubled
C) the electric field is halved
D) the electric field is doubled
E) the surface charge density is not changed on either plate

Question 8

The capacitance of a spherical capacitor with inner radius a and outer radius b is proportional to:

A) a/b
B) b - a
C) b² - a²
D) ab/(b - a)
E) ab/(b² - a²)

Question 9

The capacitance of a single isolated spherical conductor with radius R is proportional to:

A) R
B) R²
C) 1/R
D) 1/R²
E) none of these

Question 10

Let Q denote charge, V denote potential difference and U denote stored energy. Of these quantities, capacitors in series must have the same:

A) Q only
B) V only
C) U only
D) Q and U only
E) V and U only

Question 11

Let Q denote charge, V denote potential difference and U denote stored energy. Of these quantities, capacitors in parallel must have the same:

A) Q only
B) V only
C) U only
D) Q and U only
E) V and U only

Question 12

Two identical capacitors, each with capacitance C, are connected in parallel and the combination is connected in series to a third identical capacitor. The equivalent capacitance of this arrangement is:

A) 2C/3
B) C
C) 3C/2
D) 2C
E) 3C

Question 13

Capacitor C₁ is connected alone to a battery and charged until the magnitude of the charge on each plate is 4.0 x 10^-8C. Then it is removed from the vattery and connected to two other capacitors C₂ and C₃, as shown.The charge ont he positive placte of C₁ is then 1.0x 10^-8C.The charges on the positive plates of C₂ and C₃ are:

A) q₂ = 3.0 x10^--8 C and q₃ = 3.0 x 10^-18C
B) q₂ = 2.0 x10^-8 Cand q₃ = 2.0 x10^-8C
C) q₂ = 5.0 x 10^-8 Cand q₃ = 1.0x 10^-8C
D) q₂ = 3.0 x10^-8C and q₃ = 1.0x10^-8C
E) q₂ = 1.0 x10^-8Cand q₃ = 3.0 x10^-8C

Question 14

A 20-F capacitor is charged to 200 V. Its stored energy is:

A) 4000 J
B) 4 J
C) 0.4 J
D) 2000 J
E) 0.1 J

Question 15

A charged capacitor stores 10 C at 40 V. Its stored energy is:

A) 400 J
B) 4 J
C) 0.2 J
D) 2.5 J
E) 200 J

Question 16

Capacitors A and B are identical. Capacitor A is charged so it stores 4 J of energy and capacitor B is uncharged. The capacitors are then connected in parallel. The total stored energy in the capacitors is now:

A) 16 J
B) 8 J
C) 4 J
D) 2 J
E) 1 J

Question 17

To store a total of 0.040 J of energy in the two identical capacitors shown, each should have a capacitance of:

A) 0.10 $\mu$ F
B) 0.50 $\mu$ .10 $\mu$ F
C) 1.0 $\mu$ F
D) 1.5 $\mu$ F
E) 2.0 $\mu$ F