Question 1

There are approximately 10 explosions in the US every year due to agricultural grain (corn and soybean)dust.Why is corn dust so dangerous?

Accepted Answer

A) Corn contains a lot of oil and is therefore very flammable. 
B) Grain elevators use a lot of flammable material while processing the corn. 
C) Corn dust has a lot of surface area and can be ignited by even a very small spark, which can be created simply by a person walking around. 
D) Due to the presence of lots of agricultural material, grain elevators are especially rich in oxygen. 
E) Workers are not careful about where they throw their cigarette butts, and sometimes set the corn on fire. 
A) Corn contains a lot of oil and is therefore very flammable. 
B) Grain elevators use a lot of flammable material while processing the corn. 
C) Corn dust has a lot of surface area and can be ignited by even a very small spark, which can be created simply by a person walking around. 
D) Due to the presence of lots of agricultural material, grain elevators are especially rich in oxygen. 
E) Workers are not careful about where they throw their cigarette butts, and sometimes set the corn on fire. C

Question 2

Capacitor C1 and C2 are connected in parallel.The equivalent capacitance is given by:

Accepted Answer

A) C1C2/(C1 + C2) 
B) (C1 + C2)/C1C2 
C) 1/(C1 + C2) 
D) C1/C2 
E) C1 + C2 
A) C1C2/(C1 + C2) 
B) (C1 + C2)/C1C2 
C) 1/(C1 + C2) 
D) C1/C2 
E) C1 + C2 E

Question 3

An air-filled parallel-plate capacitor has a capacitance of 1 pF.The plate separation is then doubled and a wax dielectric is inserted, completely filling the space between the plates.As a result, the capacitance becomes 2 pF.The dielectric constant of the wax is:

Accepted Answer

A) 0.25 
B) 0.50 
C) 2.0 
D) 4.0 
E) 8.0 
A) 0.25 
B) 0.50 
C) 2.0 
D) 4.0 
E) 8.0 D

Question 4

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

Accepted Answer

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

The capacitance of a cylindrical capacitor can be increased by:

Accepted Answer

A) decreasing both the radius of the inner cylinder and the length 
B) increasing both the radius of the inner cylinder and the length 
C) increasing the radius of the outer cylindrical shell and decreasing the length 
D) decreasing the radius of the inner cylinder and increasing the radius of the outer cylindrical shell 
E) only by decreasing the length 
A) decreasing both the radius of the inner cylinder and the length 
B) increasing both the radius of the inner cylinder and the length 
C) increasing the radius of the outer cylindrical shell and decreasing the length 
D) decreasing the radius of the inner cylinder and increasing the radius of the outer cylindrical shell 
E) only by decreasing the length

Question 6

A parallel-plate capacitor, with air dielectric, is charged by a battery, after which the battery is disconnected.A slab of glass dielectric is then slowly inserted between the plates.As it is being inserted:

Accepted Answer

A) a force repels the glass out of the capacitor 
B) a force attracts the glass into the capacitor 
C) no force acts on the glass 
D) a net charge appears on the glass 
E) the glass makes the plates repel each other 
A) a force repels the glass out of the capacitor 
B) a force attracts the glass into the capacitor 
C) no force acts on the glass 
D) a net charge appears on the glass 
E) the glass makes the plates repel each other

Question 7

A dielectric slab is slowly inserted between the plates of a parallel plate capacitor while the capacitor is connected to a battery.As it is being inserted:

Accepted Answer

A) the capacitance, the potential difference between the plates, and the charge on the positive plate all increase 
B) the capacitance, the potential difference between the plates, the charge on the positive plate all decrease 
C) the potential difference between the plates increases, the charge on the positive plate decreases, and the capacitance remains the same 
D) the capacitance and the charge on the positive plate decrease but the potential difference between the plates remains the same 
E) the capacitance and the charge on the plate increase but the potential difference between the plates remains the same 
A) the capacitance, the potential difference between the plates, and the charge on the positive plate all increase 
B) the capacitance, the potential difference between the plates, the charge on the positive plate all decrease 
C) the potential difference between the plates increases, the charge on the positive plate decreases, and the capacitance remains the same 
D) the capacitance and the charge on the positive plate decrease but the potential difference between the plates remains the same 
E) the capacitance and the charge on the plate increase but the potential difference between the plates remains the same

Question 8

A battery is used to charge a parallel combination of two identical capacitors.If the potential difference across the battery terminals is V and the total charge Q flows through the battery during the charging process then the charge on the positive plate of each capacitor and the potential difference across each capacitor are:

Accepted Answer

A) Q/2 and V/2, respectively 
B) Q and V, respectively 
C) Q/2 and V, respectively 
D) Q and V/2, respectively 
E) Q and 2V, respectively 
A) Q/2 and V/2, respectively 
B) Q and V, respectively 
C) Q/2 and V, respectively 
D) Q and V/2, respectively 
E) Q and 2V, respectively

Question 9

A farad is the same as a:

Accepted Answer

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

Question 10

Two parallel-plate capacitors with the same plate area but different capacitance are connected in parallel to a battery.Both capacitors are filled with air.The quantity that is the same for both capacitors when they are fully charged is:

Accepted Answer

A) potential difference 
B) energy density 
C) electric field between the plates 
D) charge on the positive plate 
E) plate separation 
A) potential difference 
B) energy density 
C) electric field between the plates 
D) charge on the positive plate 
E) plate separation

Question 11

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

Accepted Answer

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

Question 12

The quantity (1/2)$\varepsilon$0E2 has the dimensions of:

Accepted Answer

A) energy/farad 
B) energy/coulomb 
C) energy 
D) energy/volume 
E) energy/volt 
A) energy/farad 
B) energy/coulomb 
C) energy 
D) energy/volume 
E) energy/volt

Question 13

The capacitance of a parallel-plate capacitor with plate area A and plate separation d is given by:

Accepted Answer

A) "$\varepsilon$0d/A" 
B) "$\varepsilon$0d/2A" 
C) "$\varepsilon$0A/d" 
D) "$\varepsilon$0A/2d" 
E) "$\varepsilon$d/$\varepsilon$0" 
A) "$\varepsilon$0d/A" 
B) "$\varepsilon$0d/2A" 
C) "$\varepsilon$0A/d" 
D) "$\varepsilon$0A/2d" 
E) "$\varepsilon$d/$\varepsilon$0"

Question 14

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:

Accepted Answer

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

Question 15

Which of the following is not a dielectric?

Accepted Answer

A) silicon 
B) germanium 
C) polystyrene 
D) titanium 
E) paper 
A) silicon 
B) germanium 
C) polystyrene 
D) titanium 
E) paper

Question 16

Two identical capacitors are connected in series and two, each identical to the first, are connected in parallel.The equivalent capacitance of the series connection is ________ the equivalent capacitance of parallel connection.

Accepted Answer

A) twice 
B) four times 
C) half 
D) one fourth 
E) the same as 
A) twice 
B) four times 
C) half 
D) one fourth 
E) the same as

Question 17

One of the materials listed below is to be placed between two identical metal sheets, with no air gap, to form a parallel-plate capacitor.Which produces the greatest capacitance?

Accepted Answer

A) material of thickness 0.1 mm and dielectric constant 2 
B) material of thickness 0.2 mm and dielectric constant 3 
C) material of thickness 0.3 mm and dielectric constant 2 
D) material of thickness 0.4 mm and dielectric constant 8 
E) material of thickness 0.5 mm and dielectric constant 11 
A) material of thickness 0.1 mm and dielectric constant 2 
B) material of thickness 0.2 mm and dielectric constant 3 
C) material of thickness 0.3 mm and dielectric constant 2 
D) material of thickness 0.4 mm and dielectric constant 8 
E) material of thickness 0.5 mm and dielectric constant 11

Question 18

A certain capacitor has a capacitance of 5.0 $\mu$F.After it is charged to 5 $\mu$C and isolated, the plates are brought closer together so its capacitance becomes 10 $\mu$F.The work done by the agent is about:

Accepted Answer

A) "0 J" 
B) "1.25 *10-6 J" 
C) "-1.25 * 10-6 J" 
D) "8.3* 10-7 J" 
E) "-8.3 *10-7 J" 
A) "0 J" 
B) "1.25 *10-6 J" 
C) "-1.25 * 10-6 J" 
D) "8.3* 10-7 J" 
E) "-8.3 *10-7 J"

Question 19

Capacitors C1 and C2 are connected in parallel and a potential difference is applied to the combination.If the capacitor that is equivalent to the combination has the same potential difference, then the charge on the equivalent capacitor is the same as:

Accepted Answer

A) the charge on C1 
B) the sum of the charges on C1 and C2 
C) the difference of the charges on C1 and C2 
D) the product of the charges on C1 and C2 
E) none of the above 
A) the charge on C1 
B) the sum of the charges on C1 and C2 
C) the difference of the charges on C1 and C2 
D) the product of the charges on C1 and C2 
E) none of the above

Question 20

Two parallel-plate capacitors with the same plate separation but different capacitance are connected in parallel to a battery.Both capacitors are filled with air.The quantity that is NOT the same for both capacitors when they are fully charged is:

Accepted Answer

A) potential difference 
B) energy density 
C) electric field between the plates 
D) charge on the positive plate 
E) dielectric constant 
A) potential difference 
B) energy density 
C) electric field between the plates 
D) charge on the positive plate 
E) dielectric constant

Exam 25: Capacitance

There are approximately 10 explosions in the US every year due to agricultural grain (corn and soybean)dust.Why is corn dust so dangerous?

Capacitor C1 and C2 are connected in parallel.The equivalent capacitance is given by:

An air-filled parallel-plate capacitor has a capacitance of 1 pF.The plate separation is then doubled and a wax dielectric is inserted, completely filling the space between the plates.As a result, the capacitance becomes 2 pF.The dielectric constant of the wax is:

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

The capacitance of a cylindrical capacitor can be increased by:

A parallel-plate capacitor, with air dielectric, is charged by a battery, after which the battery is disconnected.A slab of glass dielectric is then slowly inserted between the plates.As it is being inserted:

A dielectric slab is slowly inserted between the plates of a parallel plate capacitor while the capacitor is connected to a battery.As it is being inserted:

A farad is the same as a:

Two parallel-plate capacitors with the same plate area but different capacitance are connected in parallel to a battery.Both capacitors are filled with air.The quantity that is the same for both capacitors when they are fully charged is:

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

The quantity (1/2) ε\varepsilonε 0E2 has the dimensions of:

The capacitance of a parallel-plate capacitor with plate area A and plate separation d is given by:

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:

Which of the following is not a dielectric?

Two identical capacitors are connected in series and two, each identical to the first, are connected in parallel.The equivalent capacitance of the series connection is ________ the equivalent capacitance of parallel connection.

One of the materials listed below is to be placed between two identical metal sheets, with no air gap, to form a parallel-plate capacitor.Which produces the greatest capacitance?

A certain capacitor has a capacitance of 5.0 μ\muμ F.After it is charged to 5 μ\muμ C and isolated, the plates are brought closer together so its capacitance becomes 10 μ\muμ F.The work done by the agent is about:

Capacitors C1 and C2 are connected in parallel and a potential difference is applied to the combination.If the capacitor that is equivalent to the combination has the same potential difference, then the charge on the equivalent capacitor is the same as:

Two parallel-plate capacitors with the same plate separation but different capacitance are connected in parallel to a battery.Both capacitors are filled with air.The quantity that is NOT the same for both capacitors when they are fully charged is:

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Capacitor C₁ and C₂ are connected in parallel.The equivalent capacitance is given by:

The quantity (1/2) $\varepsilon$ ₀E² has the dimensions of:

A certain capacitor has a capacitance of 5.0 $\mu$ F.After it is charged to 5 $\mu$ C and isolated, the plates are brought closer together so its capacitance becomes 10 $\mu$ F.The work done by the agent is about:

Capacitors C₁ and C₂ are connected in parallel and a potential difference is applied to the combination.If the capacitor that is equivalent to the combination has the same potential difference, then the charge on the equivalent capacitor is the same as: