Electrostatic Potential and Capacitance · Question 13

The capacitance of a capacitor with charge q and a potential difference V depends on

1. both q and V
2. the geometry of the capacitor
3. q only
4. V only

The value of electric potential at a distance of 9 cm from the point charge 4 10-7 C is [Given 14 0 = 9 109 N m2 C-2]:

1. 4 102 V
2. 44.4 V
3. 4.4 105 V
4. 4 104 V

The equivalent capacitance of the system shown in the following circuit is: [figure]

1. 3
2. 6
3. 9
4. 2

An electric dipole is placed as shown in the figure. [figure] The electric potential (in 102 V) at point P due to the dipole is ( 0 = permittivity of free space and 14 0 = K) :

1. ( 58 ) qK
2. ( 85 ) qK
3. ( 83 ) qK
4. ( 38 ) qK

The angle between the electric lines of force and the equipotential surface is

1. 0
2. 45
3. 90
4. 180

Two hollow conducting spheres of radii R1 and R2 (R1 >> R2) have equal charges. The potential would be

1. More on bigger sphere
2. More on smaller sphere
3. Equal on both the spheres
4. Dependent on the material property of the sphere

A capacitor of capacitance C = 900 pF is charged fully by 100 V battery B as shown in figure (a). Then it is disconnected from the battery and connected to another uncharged capacitor of capacitance C = 900 pF as shown in figure (b). The electrostatic energy stored by the system (b) is [figure]

1. 4.5 10-6 J
2. 3.25 10-6 J
3. 2.25 10-6 J
4. 1.5 10-6 J

The distance between the two plates of a parallel plate capacitor is doubled and the area of each plate is halved. If C is its initial capacitance, its final capacitance is equal to

1. C4
2. 2C
3. C2
4. 4C

The effective capacitances of two capacitors are 3 and 16 , when they are connected in series and parallel respectively. The capacitance of two capacitors are :

1. 1.2 , 1.8
2. 10 , 6
3. 8 , 8
4. 12 , 4

Six charges +q, -q, +q, -q, +q, and -q are fixed at the corners of a hexagon of side d as shown in the figure. The work done in bringing a charge q0 to the centre of the hexagon from infinity is ( 0 - permittivity of free space) [figure]

1. -q24 0 d (6 - 1 2 )
2. Zero
3. -q24 0 d
4. -q24 0 d (3 - 1 2 )