Capacitors Questions and Answers

2 A 3uF capacitor is charged to a potential of 100 V and 2 F capacitor is charged to 100 V The capacitors are then connected in parallel with plates of opposite polarities joined together The amount of charge flown one to another is 1 500 C 2 100 C 3 200 C 4 240 C

8 The reactance of a capacitance C is X If both the frequency and capacitance be doubled then new reactance will be a X c 4X d X 4 b 2X

In the circuit shown find C if the effective capacitance of the whole circuit is to be 0 5 F All values in the circuit are in F 1 Options 7 10 2 C HH 2 3 2 F 4 F 7 MF 6 2 2 2 E 2 1 B

17 Two capacitor with initial charges CV and 2CV as shown in figure are connected across an inductor o inductance L Find time period of oscillation and maximum current sions of Aakash Educaough the circuit C 2CV

10 An ideal air filled parallel plate capacitor consists of two circular plates each of radius 0 30 mm How far apart should the plates be for the capacitance to be 300 0 pF A 0 0083 m B 0 0042 m C 0 00094 m D 0 00047 um

A 5 00 nF parallel plate capacitor contains 25 0 p of stored euerg a W potential difference across the capacitor b Bly how many volts would increase this potential difference in order for the capacitor to store 50 0 al energy 7 points

The figure shows an arrangement of fou parallel conducting plate of area A each All the plates are equally separated by d The plates A and D are joined togethe and a battery of emf E volt is attached between plates B and C Effective capacitance of the arrangement across the battery is 1 3 E 2 A 3 d A d A B C D 2 4 3 A 2 d 3 A d

in the circuit shown V 12Volts Ri 70 R 1950 and C 50uFarads the capacitor is initially uncharged Determine the charge on the capacitor aher the switch has been closed for a long time t mn R R 2 CF

A parallel plate capacitor with air between plates has capacity of 1 pF Now plates are moved apart with insulating handle so that separation is twice of original value The space between plates is filled with a medium of dielectric constant 6 The new value of capacity in pF is 2 3

30 180 Mark for Review Unchanged A slab of material of dielectric constant 3 has the same area A as the plates of parallel plate capacitor 3 and thicknessd where d is plate separation The 4 new capacity when slab is inserted between the plates is Twice the original value Thrice the original value 02 59 hr min Four times the original vol

Two capacitors 2 F and 4 F are connected in parallel A third capacitor of capacitance 3 F is connected in series This combination is connected across a 12 V battery The potential drop across 3 F capacitor is 4 V 3 V 2 6 V

A parallel plate capacitor has each plate area A and separation d Charge Q is given to positive plate of capacitor The force on each plate of capacitor is 0 280A 80 A 20 80A 1 4 A

A capacitor of capacitance 10 F is charged to 40 V and second capacitor of capacitance 15 F is charged to 30 V If they are connected in parallel with identical polarity The amount of charge that flows from smaller capacitor to higher capacitor is 320 C 200 C 60 C

60 An insulator plate is passed through the plates of a capacitor Then current outside the capacitor A B 1 First flows from A to B and then from B to A 2 First flows from B to A and then from A to B 3 Always flows from B to A A Abunua

A parallel plate capacitor has a plate area of 0 3m and a plate separation of 0 1 mm If the charg on each plate has a magnitude of 5x10 C if the force exerted by one plate on the other has magnitude F in N nearly and electric field due to one plate of capacitor between plate is E Ther A F 5N E 50x100 N C B F 5N E 50x10 N C 3 6 D none of these C F 5 5 N E 50x10 68 N C

In figure a potential of 12V is given to point A and point B is earthed If the potential at the point P is x and charge on 4 F is q then 4uF A x 4 q 16 C B x 8 q 8 C C x 4 q 8 C D none of these 3 F P 2 F B

Two condensers of capacities 2C and C are joined in parallel and charged up to potential V The battery is removed and the condenser C is filled completely with a medium of dielectric constant k The P D across the capacitors will now be A 3V k 2 B k 2 3V YOU C 3V k D O V k 2

For the circuit shown in the figure potential across capacitor of capacitance Cis HHHI C 5V 20 wwww 602 20 V O 5 V O 10 V 492

In the circuit shown each capacitor has a capacitance C The emf of the cell is e If the switch S is closed Then select correct statement s A some positive charge will flow out of the positive terminal of the cell TO ye B some positive charge will enter the positive terminal of the cell C the amount of charge flowing through S will be 2 Ce D the amount of charge flowing through the cell will be Ce est u

In the given figure potential at different points are given Choose the correct option s A potential at point O is 36 V 11 B potential at point O is 47 v C charge on 1 F capacitor is II D charge on 4 F capacitor is C C 4 F 6v H 5v 3 F 1 F HH 3v 3 F 3v

A dielectric slab K 4 is put between the plates of a charged parallel plate capacitor If charge on the positive plate of the capacitor is Q then the induced charge on the face of the slab that faces the positive plate will be 1 30 4 3 3Q 2 4 S 0 4 ol

Charges Q and Q are given to two plates of a parallel plate capacitor The capacity of the capacitor is C When the switch is closed mark the incorrect statement s Assume both Q and Q2 to be positive A the charge flowing through the switch is zero B the charge flowing through the switch is 2 Q C potential difference across the capacitor plate is D the charge of the capacitor is Q C

In figure the charges on C C and C3 are Q Q and Q3 respectively Then which of the following option is correct A Q 8 C B Q3 12 C C Q 20 C D potential difference across C3 is 4V C 4uF C 2uF C 3 F HE OY

the R C circuit as shown initially capacitor is charged to potential Vo with polarity as shown Switch Sis closed at f 0 At f to current through Ris half of its initial va to RC In 2 to RC In Att to potential across capacitor is zero

A parallel plate capacitor has plates of area A separated by distance d between them It is filled with a dielectric which has a dielectric constant that varies as k x K 1 ax where x is the distance measured from one of the plates If ad 1 the total capacitance of the system is best given by the expression Main 7 Jan 2020 I ad a AK 0 d 2 A en K 1 ad d 2 b c d A Eo K d 1 a d 1 2 AK 0 1 ad d

Two capacitors C 1 F and C 2 F are connected in series as shown in figure Their breakdown voltages are 12 kV and 8 kV respectively C C Find maximum safe voltage in kV which can be applied across points A and B A HHH B

20 Two point charges q 3 C and q 3 C are located 20cm apart in vacuum a What is the electric field at the mid point O of the line AB joining the two charges b If a negative test charge of magnitude 1 5x10 C is placed at this point what is the force experienced by test charge 5

Three capacitors A B and C are connected with battery of emf All capacitors are identical initially If dielectric slab is inserted between plates of capacitor C slowly with help of external force then A E B 1 Chemical energy of battery remains unchanged 2 Positive work is done on the given system by external force 3 Force between plates of capacitor B decreases 4 Magnitude of change of charge on B and C is same

A capacitor is kept connected to the battery and a dielectric slab is inserted between the plates During this process MP PMT 1994 a No work is done b Work is done at the cost of the energy already stored in the capacitor before the slab is inserted c Work is done at the cost of the battery d Work is done at the cost of both the capacitor and the battery

A capacitor consists of two fixed semicircular plates of radius R and a movable slab of thickness d and dielectric constant k placed between then The slab can freely rotate about the axis O and practically fills the entire gap between the fixed plates A constant voltage V is maintained between the plates If the torque acting on the dielectric slab when the slab is displaced to an angle 0 as shown k 1 R V nd in the figure due to electrostatic force is t 0 find the value of n 4

0 In all other cases A parallel plate capacitor contains a mica sheet thickness 10 3 m and a sheet of fibre thickness 0 5 10 m The dielectric constant of mica is 8 and that of the is 2 5 Assuming that the fibre breaks down when subjected to an electric field of 6 4 x 106 V m Find the maximum safe voltage that can be applied to the capacitor

A capacitor of capacity C is charged to the potential of V On disconnecting with battery It is connected with a capacitor of capacity C as shown in figure The ratio of energies before and after the connection of switch Swill be O C 0 G O C C C CV C 21

Two metal plates form a parallel plate capacitor The distance between the plates is d A metal plate of thickness b d 2 and same area is inserted completely between the plates What is the ratio of the capacitance in first to second case

For the circuit shown in the figure initially capacitor C is uncharged Switch S is closed at t 0 Vo 0 10 At t to potential across capacitor is Vo If current 2 through capacitor is then to Vo 3R 4R 2RC 3 R In 2 2R www

In the figure shown the capacitor of capacitance C is initially uncharged and the switch S is closed at t 0 At a later time t t the charge in the capacitor plates is found to be CV 3 Choose the correct statement s from the following as the capacitor plates get charged A The rate of heat dissipation in the resistor is going to decrease with time B The energy of the capacitor is going to increase with time C The rate of work done by the battery is going to increase with time D The charge in the capacitor plates at a time t 2t will be 2CV 3 V S

As shown the capacitors are charged to a potential difference of 100 V but with opposite polarity After switches S and S are closed what amount of charge goes through S 300 pc 300 C 50 C 200 C 150 C None of them 250 C 350 uc 50 C 350 C 100 UC 100 C 150 C 400 UC 1 F 400 C 200 C T 5 52 3 F

Seven A and successive separation d are arranged as shown in figures The effective capacitance of the system between P Q is 1 2 3 P 780A d 6E0A d 580 A d

A parallel plate capacitor is of area 6 cm and a separation 3 mm The gap is filled with three dielectric materials of equal thickness see figure with dielectric constants K 10 K 12 and K3 14 The dielectric constant of a material which when fully inserted in above capacitor gives same capacitance would be K K K3 3 mm Options 1 36 2 12 3 4

o 0 in case if no response is typed selected In the circuit shown in the figure 1 12 ls la denote current in the branches Choose the correct option www wwww R www 3R 14 ww 13E 2E www 2R www 4R 4E www ER 01 12 13 14 01 12 13 14 Oh b b h

C 0 D None 39 Capacitance of a parallel plate capacitor increases three times when the air medium in b the capacitor was replaced by oil Dielectric constant of the oil is B 3 D None A 1 3 C 9

Three identical square plates each of surface area A are arranged as shown in the figure Plates 1 2 and 3 are given charges 2Q Q and Q respectively Find out the correct options a auf ufgl Ma uz ch chi you A fa uzkfa fy og Hjuz waka 1 2 3 T 2Q Q ar de f qu 21 ad f geu 37 2Q B d A Charge on the two faces of the middle plate are 2Q and Q deg ufchicit zat kach uz 3nde 20 Correct Answer C 2 3 Energy of the system is 24 A 5 Q d Acha Juf 3 0 4 2 2 A Correct Answer Energy of the system is 3 024 2 A d A Pachy of Guf 3 0 4 2 A 2 D Charges on the two faces of the middle and if plates 1 and 3 are plate are connected through a conducting wire f 1 a 3 cy W DR gu u a ku Q a dat acht 2

iii 100 plates each of area A are arranged with the separation of d between each of them Even plates are connected to a potential of 50 volt and odds are connected to a potential of 30 volt What is the capacitance of the system 1

A The capacitance of a capacitor is the magnitude of net charge present on the two platen the potential difference between the plates B The equivalent capacitance of two capacitors in parallel is always the sum of the two cap C A dielectric material inserted between the plates of a capacitor increases its capacitanca D The electrostatic energy stored in a capacitor is always equal to energy lost as hea connected across a battery

A parallel plate capacitor is to be designed with a voltage rating 1 kV using a material of dielectric constant 3 and dielectric strength about 107 Vm Dielectric strength is the maximum electric field a material can tolerate without breakdown i e without starting to conduct electricity through partial ionisation For safety we should like the field never to exceed say 10 of the dielectric strength What minimum area of the plates is required to have a capacitance of 50 pF

6 A capacitor is made of a flat plate of area A and a second plate of stair like structure as shown in the figure The area of each stair is A and the height is d The capacitance of the 3 arrangement is A a A 3 To d b d 68 A A 3 d 0 A 3 3 A 118 A

Initially switch S is open in the given circuit If it is closed then 1 HT HH C C A B 3 Charge CV 3 CV 6 V Charge to bel 2 There is no flow of charge through switch CV S C flows from B to A que isiq flows from A to B de

This section contains 35 SINGLE questions Each question has 4 choices 1 Read More he circuit shown in the figure the charge stor capacitor of capacitance 30 F is 15 F 360 C 60 C 180 C 30 F 40 V 90 F

citors i e parallel series for combination o f dielectrics capacitors Eg Here in this question why C2 and C3 are in series with themselves and parallel with C1 4 2 A 2 V 11 dia Curte Find capacitance St

Five identical conducting plates each of face area A are arranged as shown in figure If a potential difference of Vo is created between plate A and C then the charge on plate E will be Given C woA d 1 N d d 2d d A B D E

A parallel plate capacitor filled with air has a plate area A plate separation d and a capacitance C A flat slab of metal with a similar cross sectional area and thickness d 4 is inserted in the air gap keeping the slab parallel to the terminal plates The modified capacitance is A 4C B C 4 3 3C 4 C