### CHAPTER # 12 ELECTROSTATICS

1.         One coulomb is that unit of charge which when placed at 1m form an equal and similar charge repels it with a force

a) 5 X 109 dyn         b) 5 x 109 N
c) 9 x 109 dyn          d) 9 x 109 N

2.         The minimum charge on an abject is

a) 1 coulomb           b) 1 state coulomb
c) 1.6 x 10-19            d) None

3.         Which of the following is correct

a) J = C/V               b) J = V x A
c) J = V/A               d) J = C x V

4.         One electron volt is

a) 1.6 x 10-12 ergs    b) 4.8 x 10-10 ergs
c) 300 ergs             d) None

5.         Polarization of matter is possible only for

a) Conductors         b) Insulators
c) Gases                 d) S. conductors

6.         The charge on the electron was calculated by

c) Millikon               d) Einstein

7.         The ink used in the photocopy machine

a) Black                  b) Blue
c) Red                    d) Tonar

8.         There are two charges 1 uc and 6 uc, the ratio of forces acting on them will be

a) 1:25                    b) 1:6
c) 1:1                      d) 6:1

9.         An electric field lines provides information about ________

a) Electric Force      b) Direction
c) Medium                             d) All of them

10.      If two charges are experiencing a force of 10 N, when medium is Air, if the medium is change whose permittivity is ‘2’ then force will be

a) 3 N                     b) 5 N
c) 10 N                    d) 0.3 N

11.      Unit of electric flux is

a) V.m                    b) N/C
c) V.m2                                       d) N2/C2

12.      Gauss’s law can be applied to

a) Plane surface      b) Curved surface
c) Any surface         d) Closed surface

13.      Objects may acquire an excess or deficiency of charge by

a) Electric force       b) Heating
c) Striking               d) By rubbing

14.      Coulomb’s law is only applicable for

a) Big charges         b) Small charges
c) Point charges      d) Any charges

15.      The force per unit charge is known as

a) Electric flux         b) Electric potential
c) Electric intensity   d) Electric current

16.      Electric field intensity is also known as

a) Electric potential              b) Electric flux

17.      A basic technique when applying gauss’s law is to

a.     Assume the field is constant in direction
b.    Assume the field is constant is magnitude
c.     Assume the field is constant in both magnitude and direction
d.    Construct and imaginary surface

18.      The work done in moving a charge along an equipotential surface is

a.     Depends on the path taken
b.    Greater then zero
c.     Equal to zero
d.    Negative

19.      In the region where the electric field is zero, the electric potential is always

a) Positive              b) Negative
c) Constant d) Zero

20.      The electric intensity is expressed in unit of N/C or
a) Volts                   b) Walt
c) Joules                 d) V/m

21.      The energy stored in the capacitor is

a) ½  CV2                b) ½ C2  V
c) ½ QV2                 d) ½ Q2V

22.      A charge of 0.01c accelerated through a p.d of 1000v acquires K-E

a) 10 J                    b) 100 J
c) 200 J                  d) 400 eV

23.      If the charge on the particle is double then electric field is

a) Half                    b) Double
c) Unchanged          d) None

24.      The electric potential at a point of distance 1 m from 2 uc charge is

a) 1.8 x 106 V          b) 1.8 x 106 N/C
c) 1.8 x 104 V          d) 1.8 x 105 V

25.      Capacity of a capacitor depends upon

a.     Size of plate
b.    Distance b/w plates
c.     Nature of dielectric b/w plates
d.    All of above

26.      The area of plates of 1 farad capacitor separated 8.85mm placed in the air is

a) 109m2                                    b) 05m2
c) 10-9m2                                   d) 10-15m2

27.      A capacitor acts as blocking elements when applied signal is

a) A.C                     b) D.C
c) Digital                 d) None

28.      Inkjet printers works on the principle of

a) Electrostatic               b) Electro dynamics
c) Electro magnetism     d) Electronics

29.      The surface consider for gauss’s law is called

a) Closed surface            b) Spherical surface
c) Gaussian surface         d) None

30.      One giga electron volt

a) 106 ev                 b) 109 ev
c) 1012 ev                d) 1015 ev

31.      Gravitational force does not depends on

a) Force                  b) Masses
c) Distance             d) Medium

32.      Charge to mass ratio was firsts found by

a) Millikon               b) J.J. Thomson
c) Newton               d) None

33.      The medium used b/w the plates of capacitor is called

a) Polarization         b) Dielectric
c) Insulators            d) Medium

34.      The automobiles wind shield wipers works on

a.     Electricity
b.    Cell
c.     Charging and discharging of capacitor
d.    None

35.      Selenium is a conductor material which when exposed to ________

a) Light                                                              b) Dark
c) Mono chromatic light              d) None of these

37.      When capacitors are connected in parallel the net capacitance will

a) Increase              b) Decrease
c) Constant                         d) None

38.      When two capacitors of same capacitance are connected in parallel and then in service, the capacitance in these two cases are in ratio of

a) 1:4                      b) 4:1
c) 6:1                      d) 1:2

39.      S.I unit of permittivity of free space is

c) c2/N.m2                               d) c2/N.m

40.      A capacitors may be considered as a device for

a.     Storing energy
b.    Increasing resistance
c.     Decreasing resistance
d.    None

41.      If a 10MF and 2000MF capacitors are connected in parallel the net capacitance will be

a) 6.7 uF                 b) 1990 uF
c) 2010 uF               d) None

42.      A method for charging a conductor without bringing a charge body in contact with it is called

a.     Magnetization
b.    Electrification
c.     Electrostatic induction
d.    Electromagnetic induction

43.      The field inside the hollow conductor will be

a) Zero                    b) Greater than zero
c) E = kq/r2                           d) Infinite

44.      One volt is

a.     One joule per coulomb
b.    One dyne per coulomb
c.     One Newton per coulomb
d.    One watt per second

45.      If the potential difference on a surface is equal to zero b/w any two points, then surface is said to be

a.     A dielectric
b.    An equipotential surface
c.     Polarized
d.    None

46.      The electric flux through the surface of hollow sphere containing a point charge at its center depends upon

b.    Surface area
c.     Magnitude of charge
d.    None of these

47.      A charge of 2c is in a field of intensity 2N/C, the force on the charge is

a) 1 N                     b) 4 N
c) 4 N                   d) 0 N

48.      A line whose tangent at each point is in the direction of electric intensity at that point is called a line of

a) Voltage               b) Electric force
c) Charge                d) Potential field

49.      A unit of electric charge is

a) Volt                    b) Hennery
c) Ampere               d) Coulomb

50.     Coulomb Law is also known as

a. Electrostatic Law             b. Force Law
c. Inverse Square Law                      d. None

51.  The ratio of the force between two small spheres
with constant charges A) in air,  B) in a medium
of dielectric constant K is

a) K2 : 1                                    b) 1 : K
c) K : 1                         d) 1 : K2

52.        The force of proton in electric field of magnitude 106 N/c is

a) 1.6 × 10-15N                     b) 1.6 × 109N
c) 1.6 × 1013N                      d) 1.6 × 1013N

53.        A cylinder of radius R and length L is placed in a uniform electric field E parallel to the cylindrical axis. The total flux for the surface of the cylinder is:

a)              b) Zero
c)                        d)

54.        In an inkjet printer the charged ink drops are diverted by the deflection plates

a) Towards the charging electrodes
b) Towards the gutter
c) Towards a blank paper on which the print is to
be taken
d) In inkjet printer ink can not be charged

55.        The constant K in Coulomb’s Law depends upon

a) Nature of medium            b) System of units
c) Intensity of charge           d) a & b

56.        How many electrons are in one Coulomb?

a) 6.2 × 10-23                        b) 6.2 × 10-21
c) 1.6 × 10-19                        d) Zero

57.        The force between two charges in 8N. now placed a mica of relatively 4 between two charges as a medium, the force then reduced to

a) 2N                                  b) 4N
c) 6N                                  d) 8N

58.        Selenium is an

a) Insulator              b) Conductor
c) Semiconductor    d) Photoconductor

59.        Find the potential at a point, where a charge of
1 × 10-3 coulomb is placed at a distance of 10m is

a) 1mV                                b) 1.9KV
c) 1.6KV                 d) 0.15KV

60.  In Milikan’s experiment, we find the e/m for

a) Atom                        b) Electron
c) Proton                      d) Neutron

61.        The charge determined by the Milikan’s experiment is
a)                         b)
c)                        d) None

62.        The ratio of electrostatic force to the gravitational force between them is of the order of

a) 1036                                 b) 1038
c) 1040                                 d) 1042

63.        The magnitude of the electric field on the surface of a sphere of radius ‘r’ having a uniform surface charge density  is

a)                                  b)
c)                   d)

64.        Of the following quantities, the one that is vector in character is an electric

a) Charge                b) Field
c) Energy                d) Potential Difference

65.        Dielectric has the charge of the type inside it

a) Moving charge    b) Static charge
c) Both a & b                      d) None of these

66.        The Coulomb’s force between two charges q1 and q2 separated by distance ‘r’ is F. If the separation between two charges is doubled keeping charges constant, then Coulomb’s force becomes

a) 4F                                   b) F/4
c) F/2                                  d) 2F

67.        The dimensions of relative permittivity are

a) [A2T4ML-3]                        b) [ML-3A2T4]
c) [ML3A2T2]             d) None

68.        An alpha particle has twice the charge of a proton. Two protons separated by a distance ‘d’ exert a force ‘F’ on each other. What must be the separation between the alpha particles so that they also exert a force ‘F’ on each other?

a) 2d                                   b)
c) d                              d)

1. can u please mention the correct answers of above given mcqs..

### COMMON COLLECTOR CONFIGURATION OF A TRANSISTOR

COMMON COLLECTOR CONNECTION

In  this  configuration  the  input  is  applied  between the  base  and  the  collector and  the  output  is  taken  from  the  collector  and  the  emitter.  Here  the  collector  is common to both the input and the output circuits as shown in Fig.

Common Collector Transistor Circuit

In  common  collector  configuration  the  input  current  is  the  base current  IB  and  the output current is the emitter current IE. The ratio of change in emitter current to the  change in the base current is called current amplification factor.

It is represented by

COMMON COLLECTOR CIRCUIT

A test  circuit  for determining the  static characteristic  of an NPN transistor is shown in Fig. In this circuit the collector is common to both the input and the output circuits.   To   measure   the   base   and   the   emitter   currents,   milli   ammeters   are connected in series with the base and the emitter circuits. Voltmeters are connected   across the input an…