NEET Physics Capacitors Grouping of Capacitors Energy Stored in a Capacitor and Van de Graff generator MCQs Set A

Question: On decreasing the distance between the plates of a parallel plate capacitor, its capacitance

a) increases

b) first increases then decreases

c) decreases

d) remains unaffected

Answer: increases

Question: Energy is stored in a capacitor in the form of

a) electrostatic energy

b) light energy

c) magnetic energy

d) heat energy

Answer: electrostatic energy

Question: If in a parallel plate capacitor, which is connected to a battery,we fill dielectrics in whole space of its plates, then which of the following increases?

a) Q and C

b) E and C

c)  V and E

d) Q and V

Answer: Q and C

Question:  When air in a capacitor is replaced by a medium of dielectric constant K, the capacity

a) increases K times

b) remains constant

c) decreases K times

d) increases K² times

Answer: increases K times

Question: A conductor carries a certain charge. When it is connected to another uncharged conductor of finite capacity, then the energy of the combined system is

a) less than that of the first conductor

b) equal to that of the first conductor

c) uncertain

d) more than that of the first conductor

Answer:  less than that of the first conductor

Question: The energy stored in a  condenser of capacity C which has been raised to a potential V is given by

a)

b)

c)

d)

Answer:

Question: Capacitiors are used in electrical circuits where applicances need more

a) current

b) power

c) voltage

d) resistance

Answer: current

Question: The work done in placing a charge of 8 × 10^–18 coulomb on a condenser of capacity 100 micro-farad is

a) 32 × 10^–32 joule

b) 3.1 × 10^–26 joule

c) 4 × 10^–10 joule

d) 16 × 10^–232 joule

Answer: 32 × 10^–32 joule

Question: A sheet of aluminium foil of negligible thickness is introduced between the plates of a capacitor. The capacitance of the capacitor

a) remains unchanged

b) increases

c) decreases

d) becomes infinite

Answer: remains unchanged

Question: The potential gradient at which the dielectric of a condenser just gets punctured is called

a) dielectric strength

b) dielectric number

c) dielectric constant

d) dielectric resistance

Answer: dielectric strength

Question: In a charged capacitor, the energy resides

a) in the field between the plates

b) around the edges of the capacitor plates

c) in both the positive and negative charges.

d) in the positive charges

Answer: in the field between the plates

Question:

a) zero

b) q/2

c) q

d) 2q

Answer: zero

Question:

a)

b)

c)

d)

Answer:

Question:

a)

b)

c)

d)

Answer:

Question:

a) II only

b) I, II and III

c) I only

d) I and II

Answer:  II only

Question:

a)

b)

c)

d)

Answer:

Question: A parallel plate capacitor is located horizontally such that one of the plates is submerged in a liquid while the other is above the liquid surface. When plates are charged the level of liquid

a) rises

b) falls

c) remains unchanged

d) may rise or fall depending on the of charge amount

Answer: rises

Question:  What is the effective capacitance between points X and Y?

a)

b)

c)

d)

Answer:

Question:Assertion : When a dielectric slab is gradually inserted between the plates of an isolated parallel-plate capacitor, the energy of the system decreases.
Reason : The force between the plates decreases

a) Assertion is correct, reason is incorrect

b) Assertion is incorrect, reason is correct

c) Assertion is correct, reason is correct; reason is not a correct explanation for assertion

d) Assertion is correct, reason is correct; reason is a correct explanation for assertion

Answer: Assertion is correct, reason is incorrect

Question: A parallel plate capacitor is charged by connecting it to a battery. Now the distance between the plates of the capacitor is increased. Which of the following remains constant ?

a) Potential difference between the plates of capacitor

b) Energy stored in the capacitor

c) Charge on each plate of the capacitor

d) Capacitance

Answer:  Potential difference between the plates of capacitor

Question: Two vertical metallic plates carrying equal and opposite charges are kept parallel to each other like a parallel plate capacitor. A small spherical metallic ball is suspended by a long insulated thread such that it hangs freely in the centre of the two metallic plates. The ball, which is uncharged, is taken slowly towards the positively charged plate and is made to touch that plate. Then the ball will

a) oscillate between the two plates touching each plate in turn

b) oscillate between the two plates without touch them

c) come back to its original position and will remain there

d) stick to the positively charged plate

Answer: oscillate between the two plates touching each plate in turn

More Questions............................................

Question: Eight drops of mercury of equal radii possessing equal charges combine to form a big drop. Then the capacitance of bigger drop compared to each individual small drop is

a) 2 times

b) 32 times

c) 4 times

d) 8 times

Answer: 2 times

Question:

a)

b)

c)

d)

Answer:

Question:

a)

b)

c)

d)

Answer:

Question:

a)

b)

c)

d)

Answer:

Question:

a) 2 C

b) 3 C

c) C

d)

Answer: 2 C

Question:

a) 9

b) 7

c) 15

d) 4.5

Answer: 9

Question: Capacitance (in F) of a spherical conductor with radius 1 m is

a) 1.1 × 10^–10

b) 9 × 10^–9

c) 10^–3

d) 10⁶

Answer: 1.1 × 10^–10

Question:

a) 9 km

b) 1.11 cm

c) 10 m

d) 1.11 m

Answer:  9 km

Question:

a) 96 pF

b) 84 pF

c) 81 pF

d) 72 pF

Answer: 96 pF

Question:  A parallel plate air capacitor has a capacitance of 100 mF. The plates are at a distance d apart. If a slab of thickness t (t < d) and dielectric constant 5 is introduced between the parallel plates, then the capacitance will be

a)

b)

c)

d)

Answer:

Question:

a)

b)

c)

d) 1

Answer:

Question: A parallel plate capacitor with air between the plates is charged to a potential difference of 500V and then insulated. A plastic plate is inserted between the plates filling the whole gap. The potential difference between the plates now becomes 75V. The dielectric constant of plastic is

a) 4 × 10^–10 joule

b) 16 × 10^–32 joule

c) 3.1 × 10^–26 joule

d) 32 × 10^–32 joule

Answer: 4 × 10^–10 joule

Question: A capacitor has two circular plates whose radius are 8cm and distance between them is 1mm. When mica (dielectric constant = 6) is placed between the plates, the capacitance of this capacitor and the energy stored when it is given potential of 150 volt respectively are

a)

b)

c)

d) None of these

Answer:

Question: Three condensor each of capacitance 2F are put in series. The resultant capacitance is

a) 2/3 F

b) 5 F

c) 3/2 F

d) 6F

Answer: 2/3 F

Question: Three capacitors are connected in the arms of a triangle ABC as shown in figure 5 V is applied between A and B. The voltage between B and C is

a) 2 V

b) 1 V

c) 1.5 V

d) 3 V

Answer: 2 V

Question:

a) two capacitors in series and the third in parallel with the combinatioin of first two

b) two capacitors in parallel and the third in series with the combinatioin of first two

c) all the three in parallel

d) all the three in series

Answer: two capacitors in series and the third in parallel with the combinatioin of first two

Question: The energy required to charge a parallel plate condenser of plate separation d and plate area of cross-section A such that the uniform electric field between the plates is E, is

a)

b)

c)

d)

Answer:

 Question: A network of six identical capacitors, each of value C is made as shown in the figure. Equivalent capacitance between points A and B is

a) 4C/3

b) 3C/4

c) C/4

d) 3C

Answer:  4C/3

Question:

a)

b)

c)

d)

Answer:

Question: Two capacitors of capacitances C₁ and C₂ are connected in series, assume that C₁ < C₂. The equivalent capacitance of this arrangement is C, where

a)

b)

c)

d)

Answer:

Question:  Four identical square plates of side a are arranged as shown. The equivalent capacity between A and C

a)

b)

c)

d)

Answer:

Question:

a)

b)

c)

d)

Answer:

Question:

a)

b)

c)

d)

Answer:

Question:  A number of capacitors each of equal capacitance C, are arranged as shown in Fig. The equivalent capacitance between A and B is

a)

b)

c)

d)

Answer:

Question:  Two parallel plate capacitors of capacitance C and 2C are connected in parallel and charged to a potential difference V. The battery is then disconnected, and the region between the plates of C is filled completely with a material of dielectric constant K. The common potential difference across the combination becomes

a)

b)

c)

d)

Answer:

Question:  An uncharged paralle plate capacitor having a dielectric of dielectric constant K is connected to a similar air cored parallel plate capacitor charged to a potential V₀. The two share the charge, and the common potential becomes V. The dielectric constant K is

a)

b)

c)

d)

Answer:

Question: A capacitor of capacity C₁ is charged upto V volt and then connected to an uncharged capacitor of capacity C₂. Then final potential difference across each will be

a)

b)

c)

d)

Answer:

Question:  A parallel plate capacitor with air between the plates is charged to a potential difference of 500V and then insulated. A plastic plate is inserted between the plates filling the whole gap. The potential difference between the plates now becomes 75V. The dielectric constant of plastic is

a) 20/3

b) 10

c) 5

d) 10/3

Answer:  20/3

Question:

a) two in series and one in parallel

b) two in parallel and one in series

c) all in parallel

d) all in series

Answer:  two in series and one in parallel

Question:

a) 5

b) 6

c) 4

d) 3

Answer: 5

Question:  A capacitor of capacitance C₀ is charged to a potential V₀ and then isolated. A small capacitor C is then charged from C₀, discharged and chaged again; the process being repeated n times. Due to this, the potential of the larger capacitor is decreased to V. The value of C is

a)

b)

c)

d)

Answer:

Question: From a supply of identical capacitors rated 8 mF, 250V, the minimum number of capacitors required to form a composite 16 mF, 1000V is 

a) 32

b) 16

c) 4

d) 2

Answer: 32

Question: A parallel plate air capacitor of capacitance C is connected to a cell of emf V and then disconnected from it. A dielectric slab of dielectric constant K, which can just fill the air gap of the capacitor, is now inserted in it. Which of the following is incorrect?

a) The charge on the capacitor is not conserved

b) The potential difference between the plates decreases K times

c) The energy stored in the capacitor decreases K times

d) None of these

Answer: The charge on the capacitor is not conserved

Question: In case of a Van de Graaff generator, the breakdown field of air is

a)

b)

c)

d)

Answer:

Question: Van de Graaff generator is used to

a) build up high voltage of few million volts

b) store electrical energy

c) decelerate charged particle like electrons

d) None of these

Answer: build up high voltage of few million volts

Question: Which of the following is / are true about the principle of Van de Graaff generator?

a) Both

b) The action of sharp points

c) The charge given to a hollow conductor is tranferred to outer surface and is distributed uniformly over it

d)  None of these

Answer:  Both

Question:

a) 3 m

b) 1.5 m

c) 2 m

d) 1 m

Answer:  3 m

Question:

a) 12 V

b) 8 V

c) 4 V

d) 6 V

Answer: 12 V

Question:  The energy required to charge a parallel plate condenser of plate separation d and plate area of cross-section A such that the uniform electric field between the plates is E, is

a) None of these

b)

c)

d)

Answer: None of these