1 2 3 Ans D Sol Q1 6m KC Q2 8m KC 1 2 1 C 1 eq 3 2 C eq m F 2 3 m m 6 K V 1 2 3 9KV Two capacitor having capacitance 8 mF and 16mF have breaking voltage 20V 80 V They are combined in series The maximum charge they can store individually in the combination is A 160 mC D None of these C 1280 mC B 200 mC Ans A Sol Q1 8 m 20 160 mC Q2 16 m 80 1280 mC So both capacitor are series so charge is equal Maximum charge is 160 mC A capacitor of capacitance 1 mF withstands the maximum voltage 6 kV while a capacitor of 2mF withstands the maximum voltage 4 kV What maximum voltage will the system of these two capacitor withstands if they are connected in series A 10 kV B 12 kV C 8 kV D 9 kV So maximum charge is 6 mKC so with stand Capacitance 1V 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 A zero B q 2 D 2q C q q A S B Ans A Sol When S is closed there will be no shifting of negative charge from plate A to B as the charge q is held by the charge q Neither there will be any shifting of charge from B to A 4 The equivalent capacitance across AB all capacitance in mF is mF 20 3 A C 48mF Ans B Sol B 9mF D None of these B A 30 6 10 2 B 17 13 A 6 10 C 5 1 D 1 e c n a t i c a p a C 1 0 7 0 t i t n U y h P t s a i s u h n E 0 2 9 1 0 2 g n W E E J T I I n e i A D 8 1 P M O C R P J So this is balanced wheatstone bridge l l 1 1 2 To form a composite 16m F 1000 V capacitor from a supply of identical capacitors marked 8m F 250 V we require a minimum number of capacitors A 40 B 32 C 8 D 2 6 The distance between plates of a parallel plate capacitor is d Another thick metal plate of thickness d 2 and area same as that of plates is so placed between the plates that it does not touch the plates The capacity of the resultant capacitor A remain same D becomes one fourth B becomes double C becomes half 10 2 B A 30 6 Ceq 1 C eq 2 30 4 1 6 6 4 1 C eq 1 1 1 30 10 1 3 30 1 2 1 3 6 Ceq So CNet C1 C2 eq 6 4 CNet eq 9 mF 30 4 36 4 JEE Physics 5 Ans B Sol 8 8 8 8 8 1000 V Total capacitors 4 8 32 Ans B Sol C e 0A d C New e A 0 d t t k k for metal plate t d 2 C New CNew 2C 2 e 2 A 0 d e d 0 A d 2 7 Three parallel metallic plates each of area A are kept as shown in the figure and charges Q1 Q2 and Q3 are given to them Edge effects are negligible Calculate the charges on the two outermost surfaces a and f A C Q Q Q 1 3 Q Q Q 1 3 2 2 2 3 Ans A a b c d e f Q Q Q 1 3 Q Q Q 1 3 B D Q Q Q 1 3 2 3 2 2 2 2 Sol Charge on outermost surface is half of total charge i e 8 In the arrangement of the capacitors shown in the figure each C1 capacitor has capacitance of 3 F and each C2 capacitor has capacitance of 2 F then equivalent capacitance of the network between the points a and b is a b C1 C1 C1 c C1 C2 C2 C1 C1 d C1 B 2 F C 4 F D Capacitance 3 2 F 2 3 3 2 3 3 a b 3 3 2 3 3 3 3 2 3 3 3 3 3 2 1 3 2 1 9 Each capacitor of capacitance C is arranged as shown in the given circuit The net capacitance between A and B is B 7C 6 D 2C A Sol B 6C 7 3C 2 3C 2 3C 2 3C 2 C C C e c n a t i c a p a C 1 0 7 0 t i t n U y h P t s a i s u h n E 0 2 9 1 0 2 g n W E E J T I I n e i l l A D 8 1 P M O C R P J 3C 7 3C 7 B A 3 A 1 F Ans A Sol i a b 3 3 3 3 A 6C 7 C C Ans A 3 1 F 10 Two capacitors of equal capacitance C1 C2 are shown in the figure Initially while the switch S is open one of the capacitors is uncharged and the other carries charge Q0 The energy stored in the charged capacitor is U0 Sometimes after the switch is closed the capacitors C1 and C2 carry charges Q1 and Q2 respectively the voltage across the capacitors are V1 and V2 and the energies stored in the capacitors are U1 and U2 Which of the following statements is incorrect 1 2 A Q0 C V1 V2 Q1 Q2 B Q1 Q2 D U0 U1 U2 Ans D Sol Both capacitor are in parallel so v1 v2 and both have capacitance equal So Q1 C1V1 Q2 C2V2 Q1 Q2 Initially Q0 C1V CV Finally Q1 C1V and Q2 C2V C1 C2 JEE Physics U 0 2 CV Q 0 Q Q 2 1 1 2 1 2 1 2 1 2 U 1 2 CV U 2 2 CV 1 2 U 0 U 1 U 2 2 CV CV 2 1 2 A 200mJ C 400mJ Ans B Sol U 1 2 2 2 2 20 400 2 200 J m Ans C 4 11 In the figure a capacitor of capacitance 2mF is connected to a cell of emf 20 volt The plates of the capacitor are drawn apart slowly to double the distance between them The work done by the external agent on the plates is B 200mJ D 400mJ 2 Fm 20 volt If distance between them double then capacitance will half 12 In the given circuit if point C is connected to the earth and a potential of 2000 V is given to point A the potential at B is A 1500 V C 500 V B …