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(Q.1) What is the direction of electric field intensity at a point on equatorial line
of dipole?
( 1 mark )
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(Q.2) Define electric dipole moment?
( 1 mark )
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(Q.3) Define electric field intensity?
( 1 mark )
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(Q.4) When does a dipole experiences maximum torque placed in uniform electric
field?
( 1 mark )
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(Q.5) What happens when an electric dipole is placed in non uniform electric
field?
( 1 mark )
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(Q.6) What is the value of electric field intensity inside a charged conductor?
Why?
( 1 mark )
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(Q.7) Explain, why two electric lines of forces cannot intersect each other.
( 1 mark )
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(Q.8) Howcan wecharge a body?
( 1 mark )
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S1and S2are two parallel concentric spheres enclosing
charges Q and 2 Q respectively as shown in Fig.The ratio of
the electric flux through S1and S 2
(Q.9)
( 1 mark )
(A)
(B)
(C)
(D)
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(Q.10) A charged particle having a charge of –3μC is placed close to a sheet of
charge having a surface charge density 5 × 10–6C m–2.The force of attraction
between the particle and the sheet of charge will be
( 1 mark )
(A) 0.487 (attractive)
(B) 0.487 N (attractive)
(C) 0.847 N (repulsive)
(D) 0.847 N (attractive)
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(Q.11) A large plane sheet of charge having surface charge density 5.0 × 10–6C
m–2lies in the XY- plane. Find the electric flux through a circular area of radius 0.1
m, if the normal to the circular area makes as angle of 60° with Z-axis. Given that
–12C2N–1 m–2
0= 8.85× 10
( 1 mark )
(A) 4.44 × 103Nm2C–1
(B) 2.44 × 103Nm2C–1
(C) 4.22 × 103Nm2C–1
(D) 2.22 × 103Nm2C–1
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(Q.12) An infinite line charge produces a field of 9 × 104NC–1at a distance of 4
cm. Calculate the linear charge density.
( 1 mark )
10–7Cm–1
(A) 2 ×
(B) 0.04 × 10–7Cm–1
(C) 4 × 10–7Cm-1
(D) 0.2 × 10–7Cm-1
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(Q.13) The electric field inside a spherical shell of uniform surface charge density
( 1 mark )
is :
(A) zero
(B) constant, different from zero
(C) proportional to the distance from the curve
(D) none of these
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The electric dipole is situated in an electric field as
shown in fig (i). The dipole is rotated about an axis
perpendicular to the plane of the paper about its axis at the
point A in anticlockwise direction. If the angle of rotation is
measured with respect to the direction of the electric field,
then the torque experienced by the dipole for different values
of angle of rotation is represented in fig (ii) will be given by
(Q.14)
( 1 mark )
(A) Curve (A)
(B) Curve (B)
(C) Curve (C)
(D) Curve (D)
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An electric dipole, consisting of two opposite charges of
( 1 mark )
2 Χ10-6C each separated by a distance 3 cm is placed in an
electric field of2 Χ105 N/C. Torque on the dipole is
(Q.15)
(A)
(B)
(C)
(D)
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(Q.16) A point charge +q is placed at mid point of a cube of side ‘L’. The electric
flux emerging from the cube is
( 1 mark )
(A)
(B)
(C)
(D) zero
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(Q.17) Two identical balls each have a mass of 10 g. What charges should these
balls be given so that their interaction equalizes the gravitational force of
attraction between them? The radii of the balls may be ignored in comparison to
the distance between them.
( 1 mark )
(A) 8.57 × 10–13C
(B) 5. 78 × 10 –13C
(C) 7.85 × 10–13C
(D) 7.58 × 10–13C
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(Q.18) Which of the following is/are false statements?
(I) An electric charge experiences a force due to the field, it
produces itself
(II) Two electric lines of force cannot intersect each other
( 1 mark )
(III)The unit of electric dipole moment is mC
(A) I and II are false
(B) II and III are false
(C) I and III are false
(D) I, II, III all are false
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(Q.19) An oil drop of 12 excess electrons is held stationary under a constant
electric field of 2.55 ×104 V m –1in Millikan's oil drop experiment. The density of
the oil is 1.26 g cm–3. Estimate the radius of the drop. Given that g = 9.81 m s–
2and e = 1. 6 × 10–19 C.
( 1 mark )
(A) 1.26 × 10–4mm
(B) 1.92 × 10–4mm
(C) 2.55 × 10–4mm
(D) 9.82 × 10–4mm
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(Q.20) Calculate the total positive or negative charge on 3.11 g copper penny.
Given Avogadro number = 6.02 × 1023 ,atomic number of copper=29 and atomic
mass of copper = 63.
( 1 mark )
(A) 2. 95 × 10 22C
(B) 85.55 × 1022C
(C) 1.37 × 105 C
(D) 14.20 × 1041C
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(Q.21) A water particle of mass 10.0 mg and having a charge of 1.50 × 10–6C
stays suspended in a room.The field will be
( 1 mark )
(A) 6.53 N/C, vertically upwards
(B) 6. 53 N/C, vertically downwards
(C) 65.3 N/C, vertically upwards
(D) 65.3 N/C, vertically downwards
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(Q.22) Calculate the electric intensity due to dipole of length 10 cm and having a
charge of 500 μC at a point on the axis at a distance 20 cm from one of the
charges in air.
( 1 mark )
(A) 32. 5 × 107NC
(B) 325 × 106 NC
(C) 3.25 × 107NC
(D) 3.25 × 106NC
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There exists a non-uniform electric field along x-axis as
shown in the figure below. The field increases at a uniform
rate along +ve x-axis. A dipole is placed inside the field as
shown. Which one of the following is correct for the dipole?
(Q.23)
( 1 mark )
(A) Dipole moves
(B) Dipole moves
(C) Dipole moves
(D) Dipole moves
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along
along
along
along
positive x-axis and undergoes a clockwise rotation
negative x-axis and undergoes a clockwise rotation
positive x-axis and undergoes an anticlockwise rotation
negative x-axis and undergoes an anticlockwise rotation
The diagram shows the electric lines of forces emerging
from a charged body. If the electric field at A and B are E Aand
EBrespectively and if the distance between A and B is r, then
(Q.24)
( 1 mark )
(A) EA> EB
(B) EA= EB/r
(C) EA< EB
(D) EA= EB/r2
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(Q.25) Two charges (+2 coulomb, –2 coulomb) are placed at a distance 0.5 m.
Then their dipole moment will be :
( 1 mark )
(A) 1 Cm
(B) 2 Cm
(C) 3 Cm
(D) 4 Cm
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(Q.26) Two charges (1 coulomb each) are placed at a distance 9 × 10–9m. Electric
force between them will be
( 1 mark )
1027
(A) 1/9) ×
N
(B) 1/9) × 10–27N
(C) (1/9)N
(D) 4 N
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(Q.27) An electric dipole is kept in a uniform electric field. it experiences
( 1 mark )
(A) A force and a torque
(B) A force, but no torque
(C) A torque but no force
(D) Neither a force nor a torque
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Equal charges q each are placed at the vertices A and B
of an equilateral triangle ABC of side a. The magnitude of
electric intensity at the point C is
(Q.28)
( 1 mark )
(A)
(B)
(C)
(D)
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(Q.29) Quantization of charge implies
( 1 mark )
(A) Charge cannot be destroyed
(B) Charge exists on particles
(C) There is a minimum permissible charge on a particle
(D) Charge, which is a fraction of a coulomb is not possible.
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(Q.30) What happens when some charge is placed on a soap bubble?
( 1 mark )
(A) Its radius decreases
(B) Its radius increases
(C) The bubble collapses
(D) None of the above
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(Q.31) Two spheres A and B of exactly same mass are given equal positive and
negative charges respectively. Their masses after charging
( 1 mark )
(A) Remain unaffected
(B) Mass of A > mass of B
(C) Mass of A < mass of B
(D) Nothing can be said
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(Q.32) The distinction between conductors, insulators and semiconductor is
largely concerned with
( 1 mark )
(A) Their ability to conduct current
(B) The type of crystal lattice
(C) Binding energy of their electrons
(D) Relative widths of their energy gaps
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(Q.33) What is the dimentional formula for
0
?
( 1 mark )
(A) M-2L1T-3A2
(B) M-1L-3T4A2
(C) M1L3T-4A-2
(D) M-3L-1T4A2
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(Q.34) How many charges form 1 coulomb of charge?
( 1 mark )
(A) 6.25x1012
(B) 6.25x1016
(C) 0.625x1012
(D) 6.25x1018
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(Q.35)
( 1 mark )
What is the electric dipole moment of an electron and a proton 4 nm apart.
(A)
6.4x10-24 Cm
(B)
6.88x10-24 Cm
(C)
6.4x10-28 Cm
(D)
3.4x10-24 Cm
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(Q.36) The potential difference between two points is 20 volt. How much work
will be done in carrying charge of 400 μ C from one point to other?
( 1 mark )
(A) 8x10-3 J
(B) 2x10-3 J
(C) 4x10-3 J
(D) 8x10+3 J
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(Q.37) Define electric flux, also mention its formula?
( 2 Marks )
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What will be the minimum electrostatic force between
two charged particles placed at a distance of 1m apart?
(Q.38)
( 2 Marks )
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(Q.39)
Define electric dipole moment. Give its direction?
( 2 Marks )
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(Q.40)
Define grounding or earthing?
( 2 Marks )
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(Q.41)
How is a neutral body electrified?
( 2 Marks )
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(Q.42)
What is a gold leaf electroscope?
( 2 Marks )
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An electric dipole, experiences a torque of 24x10-26 Nm.
When it is placed 300 w.r.t a uniform electric field of strength ( 3 Marks )
6x104 NC-1.calculate the dipole moment of the dipole?
(Q.43)
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A dipole consisting of an electron and a proton
separated by a distance 2x10-5m is situated in the electric
field intensity of 4x105 NC-1 at an angle of 30 0 with the field.
Calculate the dipole moment and the torque acting on it?
(Q.44)
( 3 Marks )
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A solid sphere contains a uniformly distributed charge
of density . What is the electric field inside the sphere at a
distance r from the centre?
(Q.45)
( 3 Marks )
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A point charge is placed at the centre of a cube.
What is the flux linked,
(Q.46)
( 3 Marks )
(a) with the cube?
(b) with each face of the cube?
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(Q.47) Two point charges +9e and e are kept at distance x apart.At what distance
a charge q should be placed from charge+e, so that q is in equilibrium.
( 3 Marks )
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A system has two charges q = 2x10-7 C and q = -2x10-7
C located at points A(0,0,-10cm) and B(0,0,+10cm)
respectively.find the total charge and electric dipole moment
of the system.
(Q.48)
( 3 Marks )
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State coulomb’s law, also derive the formula for the
same.
(Q.49)
( 3 Marks )
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(Q.50) Mention some basic properties of electric charges?
( 3 Marks )
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(Q.51)
Write, in brief, the method to determine the distance of an inferior planet from the
earth.
( 3 Marks )
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(Q.52)
( 3 Marks )
“The magnetic lines of force prefer to pass through iron than air.” Give reason,
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(Q.53)
( 3 Marks )
Why is the energy of the electron emitted during beta decay continuous?
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Give the equation for the charge desity of continuous
uniform charge distributions in the case of linear, surface and ( 5 Marks )
volume distribution of charges.
(Q.54)
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State Gauss law and derive the formula for electric field
( 5 Marks )
intensity of an infinite thin plane sheet of uniform surface
charge density .
(Q.55)
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(Q.56)
Mention some important properties of electric field
lines?
( 5 Marks )
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Derive the formula for electric field of an electric dipole
for the following two cases(a) axial line (b) equatorial line.
(Q.57)
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( 5 Marks )