Capacitors Questions and Answers

A dielectric slab of thickness d is inserted in the parallel plate capacitor whose negative plate is at x 0 and positive plate is at x 3d The slab is equidistant from the plates The capacitor is given some charge As x goes from 0 to 3d A the magnitude of the electric field remains the same B the direction of the electric field remains the same C the electric potential increases continuously D the electric potential increases first then decreases and again increases Find equivalent capacitance between A and B Assume each conducting plate is having same dimensions and neglect the A thickness of the plate 7 F where A is area of plates A d A 7 F B 11 F C 12 F YA D 13 uF d

20 In the circuit shown in the figure C C C 2C C 3C C 4C Then select CORRECT alternative s C C HHH C 2 A Maximum potential difference is across C B Minimum potential difference is across C C Maximum potential energy is in C D Minimum potential energy is in C

13 derive an expression for the capacitance of a parallel plate capacitor when a dielectric slab of dielectric constant K and thickness t d 2 but of same area as that of the plates is inserted between the capacitor plates d separation between the plates ont and also find charge stored on each capacitor

B in the given circuit is 8 F A IT HH 12 F 12 F B 8 F Sol Here 12 F and 12 F are short circuited

2 In the figure shown below the half area from the bottom is filled with a dielectric of dielectric constant T The area of the plate is A E A Equivalent capacitance of the system is EOA 1 T 2d B The net charge on the lower half of the left hand plate is 1 T times the charge of the upper half of the plate C Net charges on the lower and upper half of the left hand plate are different D Net charges on the lower half of left hand plate is T OA V 2d

Calculate the capitance between the point P and Q in the following circuit fra far print antal ari 1 5 F 1 1 5 F 2 3 F P 3 0 F HH 1 5 F 3 2 F 3 0 F 4 1 F

Live marks Awary oph A 2 F capacitor is charged to a potential 10V Another 4 uF capacitor is charged to a potential 20V The two capacitors are then connected in a single loop with the positive plate of one connected with negative plate of the other What heat is evolved in the circuit 300 600

Two identical parallel plate capacitors are connected as shown in the figure Initially both have total charge q and separation between their plates x At an instant plates of one capacitor begin to move towards each other and plates of the other capacitor away from each other If velocity of a plate relative to the other in both the capacitors has the same magnitude v find current in A in the circuit Given q 1mC x 1mm v 8m s

The effective capacitance between X and Y is approximately All capacitance in microfarads 5 10 5 5 10 3 2 F O 5 F 10 10 HH 10

n the given circuit the potential difference between point A and B is 18 V and charge on 2 F capacitor is 24 pC The energy stored in Capacitor Cis 2 F A 6 F 72 J 144pJ 36 J B

Displace current is given by Question Type Single Correct Type 1 2 3 4 Apo dE dt Hoo dE dt dE EoA dt A dE dt 140 0 Q

Consider the situation shown in the figure The capacitor A has a charge q on it whereas B is uncharged The charge appearing on the capacitor B a long time after the switch is closed is DFD O Zero 0 92 09 029 Marks 4 1

Two air filled capacitors are connected as shown The left capacitor is suddenly filled with a dielectric of constant K The work done by battery after that is 24 J Dielectric constant K is 2 F 4 F

A parallel plate capacitor is made of two plates of length 1 width oo and separated by distance d A dielectric slab dielectric constant K that fits exactly between the plates is held near the edge of the plates It is pulled into au the capacitor by a force F x is the enerey of the capacitor when dielectric is inside the capacitor up to distance x See figure If the charge on the capacitor is Q then the force on the dielectric when it is near the edge is 1 2 3 Q d K 2001 Q 0 2dl o K 1 0 d 2001 K 1 Q w K 1 where U X1 X

4 R 25 2 L 2 5 H C 45 F In an adjoining figure three capacitors C C and C3 are joined to a battery The correct condition will be V C Q V HF V C Q HH V C3Q3 3 1 Q Q Q3 and V V V V 2 Q Q Q3 and V V V V3 3 Q Q Q3 and V V V 4 Q Q3 and V V 2 Symbols have thei

14 A capacitor is charged by using a battery which is then disconnected A dielectric slab then slipped between the plates which results in 1 Point reduction of charge on the plates and increase of potential difference across the plates increase in the potential difference across the plate reduction in stored energy but no change in the charge on the plates decrease in the potential difference across the plates reduction in the stored energy but no change in the charge on the plates None of these

10 identical capacitors each of capacitance C are connected in series with a battery of emf V and fully charged Now the battery is removed and the capacitors are connected in parallel with positive terminals of 8 capacitors and negative terminals of 2 capacitors at a point and negative terminals of 8 capacitors and positive terminals of 2 at other point The common potential R charge on each capacitor is

g 14 Plates of area A are arranged as shown The distan between each plate is d the net capacitance is a c A ad 680 A d 21 780A sdfd ban b 58A 10 old d b 580A Sols F

An air filled parallel plate capacitor with the plate area A is connected to a battery with an emf V volt and negligible internal resistance One of the plates vibrates so that the distance between plates varies as d do a coswt where a do The capacitor breakes down when the instantaneous current reaches to the value of I Choose the correct options s L The maximum possible amplitude vibrations a is The maximum possible amplitude vibrations a is The instantaneous current in circuit is The instantaneous current in circuit is Id VAWEO 21d VAWO fo Va do a coswt 2 sin wt o Va 2 do a coswt sinat VT d Vibrating plate Fixed plate

194 In the arrangement shown all plates have equal area The amount of spacing between the plates is mentioned Find the charge on the plate X if battery is connected to plate A and B X A C 2L 2L CV 3 CV Y A B B WOR D CV 5 CV 9

A time varying voltage is applied across AB as shown Potential difference across the capacitor plate varies as shown Then which of the following is are correct C D V T to 21 Plot of potential difference across CD is Plot of potential difference across CD is 3t 5t t jam 3t 5t t 2t to 2t 3t 5t t Plot of current across resistance does not vary for large value of resistance capacitor n Plot of current across resistance does not vary for small value of resistance capacitor

Four parallel large plates separated by equal distance d are arranged as shown The area of the plate is S Find the potential difference between the plates B and C if the plate B is given charge Q A B C D A B K d Qd 30S Correct Answer 2Qd 380S d d

4 1 Putting a dielectric substance between two plates 6 of an isolated condenser capacity potential and potential energy respectively 1 Increase decrease decrease 2 Decrease increase increase 3 Increase increase increase 4 Decrease decrease decrease 3 2 a farafia dunia i ci s efta vas uuden TEA Tentan fara va ferfaa 1 af at 2 aft af afa 3 afa afa afa 4 ft ft

are connected as shown in the figure Initially S is open and the capacitors are uncharged After S is closed and steady state is attained the potential difference acoss the 4 F capacitor is 7 5 V The capacitance in uF of the capacitor A is S 24V H A 3 F 2 F 4 F

Two capacitors C 2uF and C 6 F in series are connected in parallel to a third capacitor C 4uF This arrangement is then connected to a battery of e m f 2 V as shown in figure The energy lost by the battery in charging the capacitors is C C C 2V 1 22 10 J 2 11 10 J

The potential difference between the points A and B and that between E and F of the circuit shown in figure respectively are 23V 4 1 15 F 0 75 F HE 5 F A 5V 5V C 15 V 5V A 5 F HE 15 F E 15 F 0 75 F H6 F 5 F B 10 V 5V D OV OV

X X capacit Column 1 formed by any two successive plates is take the count of the plates from top t Take C 3uF V 10V between X and bottom X fig 1 y fig 2 y fig 3 y y

2 The charge q on a capacitor varies with voltage as shown in figure The area of the triangle AOB represents 1 electric field between the plates 2 electric flux between the plates 3 energy density 12 y funger ufafa 1 2 3 4 9 AAOB fanga ars farger veran 4 energy stored by the capacitor Two charges g and 3q are placed on x axis 13

In the shown circuit initially capacitor is uncharged Now switch is closed find net heat loss in the circuit in J HI 2 F 4 V Answer 00 01 02 03 04 05 06 07 8 09 00 01 02 03 04 05 06 07 08 09

In the circut shown all capacitors are identical Initially the switch is open and the capacitor marked is the only one charged After the switch is closed an equilibrium is reestablished the charge on the capacitor marked is Q The initial charge is Op XQ on that capacitor Value of Xis H

tion How long does it take to fully charge a 5 F capacitor in series with a 5 MQ resistor O 125 microseconds 25 seconds 125 seconds 125 milliseconds

Find the equivalent electrical impedance between the terminals A and B shown in the figure for an alternating current of frequency The infinite chain is made up of a large number of identical units each consisting of a coil of inductance L and a capacitor with capacitance C Is it possible that the equivalent impedance has two different values C A Bo C C

SINGLE CORRECT ANSWER QUESTIONS 1 A capacitor is made of a flat plate of area A and second plate having a stair like structure as shown in figure The width of each plate is a and the height is b The capacitance of the capacitor is A B C D 2A 3 d b 3a A 3d 6bd 2b 3d b d d 2b A d 2bd b 3d d b d 2b 2A d 2bd b 3d d b d 2b a

A parallel plate capacitor is charged to potential difference V by a dc source The capacitor is then disconnected from the source If the distance between the plates is doubled then how will the following change a electric field between the plates stored in the capacitor b energy

2 A parallel plate capacitor of C is charged with a battery of emf V volts A dielectric slab of dielectric constant K is placed between the plates to fully occupy the space The battery remains connected The new electrostatic charge on the plates q is related with initial charge q as 1 K q0 2 Kqo 3 90 4 90 K C

Consider capacitance circuit consisting 12 identical capacitors each of capacitance luF as shown in the figure The equivalent capacitance between the terminals F A and E is uF 12 Hand I is HF H A I I D BY A B A and I is 8 THE D H and B is 5 THE initial charge O The su

18 Five capacitors each of capacitance C and breakdown voltage V are connected as shown in the figure The capacitance and breakdown voltage of the combination applied across AB will be 7C V A 6 2 7C 6 7C 3V 62 V 6C V A A CI HH 24 C1 a 34 11 HH V Cit N m ur B

Three plates A B C each of area 50cmt have separation 3mm between A and B and 3mm between B and C The energy stored when the plates are fully charged is C A 1 6 x 10 J C 5 x 10 J 12V B 2 1 x 10 J D 7 x 10 J

on OV 3 12 22 In the given arrangement the value of equivalent capacitance between points A and B is 1 4 F 3 2 F A 2 F 2uF 2 F 2 F B 4X 3 2 6 F A

10 In the figure shown the equivalent capacitance between A and B is 10 F 10 F HHH A 1 3 75 F 3 6 5 F 5 F 3uF HH 15 F 6 F 6uF 2 5 25 F 4 10 5 F B

A cylindrical capacitor consists of two coaxial cylinders of radii a and b as shown in the figure A battery of emf V is connected across the cylinders A uniform magnetic field B exists in the region between the cylinders A positively charged particle of charge q and mass m leaves the inner cylinder with zero initial velocity Find the minimum value of V for which the particle can reach to the outer cylinder Assume that the space is gravity free 0 0 E 1 O bo C

A parallel plate capacitor is charged with a battery until it reaches voltage V After the battery was disconnected the distance betweer the plates was increased 3 times no charge loss in this process Which of the following is true about the capacitance and the voltage between the plates as a result of this process the capacitance decreases the voltage between the plates increases O the capacitance stays the same the voltage between the plates stays the same O the capacitance increases the voltage between the plates decreases the capacitance decreases the voltage between the plates decreases O the capacitance increases the voltage between the plates increases

The between the plates of a parallel plate capacitor gap vi is filled with isotropic dielectric whose relative permittivity e varies linearly from to E E in the direction perpendicular to the plates The area of each plate is equal to A the separation between the plates is equal to d Find the capacitance of the capacitor A 4 d In 2

Four capacitors each of capacitance Care connected as shown in the figure The ratio of capacitance between P and R to the capacitance be and Qis P 0 1 1 034 23 C R

ed is S g 8 D 2 37 In the circuit shown in figure 2 296 find the equivalent capacitance between terminals A and B Ans 3uFI 8 F 2 F AH 6 F 3 F 3 F Figure 2 296 4 F 4 F HH B

For the following arrangement the charge flown through the battery will be 10 V 3 F 3 F O 10 C O 10 C O 30 C O 15 C 3 F

For the circuit as shown in the figure the net charge on upper plate will be Area of each plate is A and separation between two consecutive plate d O O 26 AV d

xi Calculate the capacitance of a parallel plate capacitor with plate area A and distance between plates d when filled with a dielectric whose dielectric constant varies as J x Bx In x E B d x For what value of would the capacitance of capacitor becomes of the capacitor twice that when it is without any dielectric d EO B 0 2 0 x d d 14 02 2 x d is given the relation d 40 In 0 Eo B 0 2 1

A 2 F capacitor is connected between points A and B in the circuit shown 60 A 30 wwwwww 2 F 12 V O 9 J O 18 J 27 J wwwwww The energy stored in the capacitor at steady state is O 36 J 302 B 6N J

A This section contains 35 SINGLE CORRECT TYPE questions Each question has 4 choices 1 2 3 and 4 out of which only one is The equivalent capacitance of the circuit shown in the figure between terminals A and B is C C C5 Phy Section A 2C 0 200 C Read More C THB