In an adjoining figure are shown three capacitors C1, C2 and C3 joined to a battery. The correct condition will be (Symbols have their usual meanings) :

  • Q1 = Q2 = Q3 and V1 = V2 = V3 = V

  • Q1 = Q2 + Q3 and V = V1 + V2 + V3

  • Q1 = Q2 + Q3 and V = V1 + V2

  • Q2 = Q3 and V2 = V3

In the circuit diagram shown in the adjoining figure, the resultant capacitance between P and Q is 

  • 47 μF

  • 3 μF

  • 60 μF

  • 10 μF

Two capacitances of capacity C1 and C2 are connected in series and potential difference V is applied across it. Then the potential difference across C1 will be:

  • VC2C1

  • VC1+C2C1

  • VC2C1+C2

  • VC1C1+C2

A capacitor of capacity C1 is charged to the potential of V0. On disconnecting with the battery, it is connected with a capacitor of capacity C2 as shown in the adjoining figure. The ratio of energies before and after the connection of switch S will be

  • (C1 + C2)/C1

  • C1/(C1 + C2)

  • C1C2

  • C1/C2

Four capacitors of each of capacity 3 μF are connected as shown in the adjoining figure. The ratio of equivalent capacitance between A and B and between A and C will be:

  • 4: 3

  • 3: 4

  • 2: 3

  • 3: 2

A parallel plate condenser is filled with two dielectrics as shown. Area of each plate is A metre2 and the separation is t metre. The dielectric constants are k1 and k2 respectively. Its capacitance in farad will be:

  • ε0At(k1+k2)

  • ε0At.k1+k22

  • 2ε0At(k1+k2)

  • ε0At.k1k22

Three condensers each of capacitance 2F are put in series. The resultant capacitance is 

  • 6F

  • 32F

  • 23F

  • 5F

Four condensers are joined as shown in the adjoining figure. The capacity of each is 8 μF. The equivalent capacity between the points A and B will be

  • 32 μF

  • 2 μF

  • 8 μF

  • 16 μF

The capacities and connection of five capacitors are shown in the adjoining figure. The potential difference between the points A and B is 60 volts. Then the equivalent capacity between A and B and the charge on 5 μF capacitance will be respectively

  • 44 μF; 300 μC

  • 16 μF; 150 μC

  • 15 μF; 200 μC

  • 4 μF; 50 μC

Four plates of the same area of cross-section are joined as shown in the figure. The distance between each plate is d. The equivalent capacity across A and B will be

  • 2ε0Ad

  • 3ε0Ad

  • 3ε0A2d

  • ε0Ad

In the adjoining figure, four capacitors are shown with their respective capacities and the P.D. applied. The charge and the P.D. across the 4 μF capacitor will be

  • 600 μC; 150 volts

  • 300 μC; 75 volts

  • 800 μC; 200 volts

  • 580 μC; 145 volts

In the connections shown in the adjoining figure, the equivalent capacity between A and B will be:

  • 10.8 μF

  • 69 μF

  • 15 μF

  • 10 μF

2 μF capacitance has potential difference across its two terminals 200 volts. It is disconnected with battery and then another uncharged capacitance is connected in parallel to it, then P.D. becomes 20 volts. Then the capacity of another capacitance will be 

  • 2 μF

  • 4 μF

  • 18 μF

  • 10 μF

The resultant capacitance across 300 v battery in the figure shown is equal to

  • 1 μF

  •  31120 μF

  • 2 μF

  • 12031μF

A capacitor is charged by a battery. The battery is removed and another identical uncharged capacitor is connected in parallel. The total electrostatic energy of the resulting system 

  • increases by a factor of 4

  • decreases by a factor of 2

  • remain the same 

  • increases by a factor of 2

The diagrams below show regions of equipotentials.

 

A positive charge is moved from A to B in each diagram. Then:

  • the maximum work is requried to move q in figure(iii).

  • in all four cases,the work done is the same.

  • the minimum work is requried to move q in the figure(i).

  • the maximum work is required to move q in figure(ii).

An electric dipole is place at an angle of 30 with an electric field intensity 2×105 N/C. It experiences a torque equal to 4 Nm. The charge on the dipole, if the dipole length is 2 cm, is

  • () 8 mC             

  • () 2 mC

  • () 5 mC             

  • () 7 μ

A parallel-plate capacitor of area A, plate separation d, and capacitance C is filled with four dielectric materials having dielectric constants k1,k2,k3 and k4 as shown in the figure below. If a single dielectric material is to be used to have the same capacitance C in this capacitor, then its dielectric constant k is given by

       

  • () k=k1+k2+k3+3k4

  • () k=23k1+k2+k3+2k4

  • () 1k=32k1+k2+k3+12k4

  • () 1k=1k1+1k2+1k3+32k4

A capacitor of 2μF is charged as shown in the figure. When the switch S is turned to position 2, the percentage of its stored energy dissipated is
       

  • 20%
  • 75%
  • 80%
  • 0%

A parallel plate air capacitor of capacitance C is connected, to a cell of emf V and then disconnected from it. A dielectric slab of dielectric constant K, which can just fill the air gap of the capacitor, is now inserted in it. Which of the following is incorrect?

  • The potential difference between the plates decreases K times

  • The energy stored in the capacitor decreases K times

  • The change in energy stored is 12CV21K-1

  • The charge on the capacitor is not conserved

If potential (in volts) in a region is expressed as V(x,y,z)=6xy-y+2yz, the electric field (in N/C) at point (1,1,0) is       


(1)-(3i^+5j^+3k^)

(2)-(6i^+5j^+2k^)

(3)-(2i^+3j^+k^)

(4)-(6i^+9j^+k^

  • 1
  • 2
  • 3
  • 4

Two thin dielectric slabs of dielectric constants K1&K2 (K1<K2) are inserted between plates of a parallel capacitor, as shown in the figure. The variation of electric field E between the plates with distance d as measured from plate P is correctly shown by  

  •  

A conducting sphere of radius R is given a charge Q. The electric potential and field at the centre of the sphere respectively are

  • () zero and Q/4πεoR
  • ()Q/4πεoR and zero

  • ()Q/4πεoR and Q/4πεoR2

  • ()Both are zero

In a region, the potential is represented by V(x,y,z)=6x-8xy-8y+6yz, where V is in volts and x,y,z are in meters. The electric force experienced by a charge of 2 coulomb situated at point (1,1,1) is

  • 6√5N
  • 30N

  • 24N

  • 4√35N

A, B and C are three points in a uniform electric field. The electric potential is

  • maximum at A

  • maximum at B

  • maximum at C

  • same at all the three points A,B and C

Four point charges -Q,-q,2q and 2Q are placed, one at each corner of the square.The relation between Q and q for which the potential at the centre of the square is zero, is 

  • Q=-q                                       

  • Q=-1q

  • Q=q                                         

  • Q=1q

Two metallic spheres of radii 1 cm and 3 cm

are given charges of -1×10-2C and 5×10-2C,

respectively. If these are connected by a conducting

wire, the final charge on the bigger sphere is

  • 2×10-2C

  • 3×10-2C

  • 4×10-2C

  • 1×10-2C

A parallel plate condenser has a uniform electric field E(V/m) in the space between the plates. If the distance between the plates is d(m) and area of each plate is A(m2), the energy (joule) stored in the condenser is

  • 12ε0E2

  • ε0EAd

  • 12ε0E2Ad

  • E2Ad/ε0

Four electric charges +q, + q, -q and -q are placed at the corners of a square of side 2L (see figure). The electric potential at point A, mid-way between the two charges +q and +q, is

                                            

  •   14πε02qL1+15

  •     14πε02qL1-15

  •     Zero

  •   14πε02qL1+5

Three charges, each +q, are placed at the corners of an isosceles triangle ABC of sides BC and AC equal to 2a. D and E are the mid points of BC and CA. The work done in taking a charge Q from D to E is 

  • eqQ8πε0α                                                 

  • qQ4πε0α

  • zero                                                     

  • 3qQ4πε0α

0:0:1


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