1 P 3 10uF 18 A parallel plate capacitor having a plate separation of 2mm is charged by connecting it to a 400V supply The energy density is 1 0 09 Jim 3 0 36 J m A charge is q kept in front of neutral metallic sphere as shown in the figure The value of electric field at the centre of sphere due to induced charge on surface of sphere is R 19 1 41 o k 1 1 Q k are ined as shown in the figure apacitor is 8pF Equivalent and B lp 1 2mm Q k 1 Q 2k 2 2 2 0 18 J m 4 0 72 J m 2 3 4neo R d 20 Two identical capacitors 1 and 2 are connected in series The capacitor 2 contains a dielectric slab of constant k as shown They are connected to a battery of emf vo volt The dielectric slab is then removed Let Q and Q be the charge stored in capacitor before removing the slab and Q and Q be the values after removing the slab Then 9 4n do 4 3q 41 o R 8 F 32pF R Q k 1 2 NIX 4 Q 3 1 In the arrangement the value of each capacitor is Xu F Then the equivalent capacitance between point a and c is In F 3 4 49 22 in the given arrangement the valu capacitance between points A and Bis 24 etquestionpaper 1 4pF 3 2uF 23 A solid sphere conducting is surrounded by metallic shell of radius 2r Initial charges on them are 5uC and 3 C respectively If both are connected by thin metallic wire then charge appearing on A and B are 1 4 C each 3 3 C and 5uC 1 3 1 2pF 0 K 1 KV K 1 7 B 5 C 2 0 and 8uC 4 2 C and 6uC There are two identical capacitors The first one is uncharged and filled with dielectric constant K while the other is charged to potential V having air between its plates If two capacitors are joined end to end the common potential wire be 2r 2 BuF 4 3uF 3 C 2 3 4 K 1 25 An uncharged sphere of metal is placed in a uniform electric field produced by two oppositely charge large plates The lines of force appear as Tall 1181 KV 2