JEE Questions for Physics Electrostatics I Quiz 21 - MCQExams.com

Three charges, each +q, are placed at the corners of an isosceles triangle ABC of sides BC and AC, 2a. D and E are the mid points of BC and CA. The work done in takinga charge Q from D to E is
Physics-Electrostatics I-72270.png
  • Zero
  • 2)
    Physics-Electrostatics I-72271.png

  • Physics-Electrostatics I-72272.png

  • Physics-Electrostatics I-72273.png
The electric field created by a point charge falls with distance r from the point charge as

  • Physics-Electrostatics I-72275.png
  • 2)
    Physics-Electrostatics I-72276.png

  • Physics-Electrostatics I-72277.png

  • Physics-Electrostatics I-72278.png
The electric potential at a point on the axis of an electric dipole depends on the distance r of the point form the dipole as

  • Physics-Electrostatics I-72281.png
  • 2)
    Physics-Electrostatics I-72282.png

  • Physics-Electrostatics I-72283.png

  • Physics-Electrostatics I-72284.png
An electric dipole is kept in non-uniform electric field. It experiences
  • A force and a torque
  • A force but not a torque
  • A torque but not a force
  • Neither a force nor a torque
An electric dipole consisting of two opposite charges of 2 × 10–6 C each separated by a distance of 3 cm isplaced in an electric field of 2 × 105 N/C. The maximum torque on the dipole will be
  • 12 × 101 Nm
  • 12 ×10–3 Nm
  • 24 × 10–1 Nm
  • 24 ×10–3 Nm

Physics-Electrostatics I-72288.png
  • pE
  • +2pE
  • –2pE
  • Zero

Physics-Electrostatics I-72290.png
  • α
  • θ
  • θ + α
  • θ + 2α
An electron dipole is placed along the x–axis at the origin O. a point P is at a distance of 20 cm from this origin such that OP makes an angle θ with the x–axis, the value of θ would be

  • Physics-Electrostatics I-72291.png
  • 2)
    Physics-Electrostatics I-72292.png

  • Physics-Electrostatics I-72293.png

  • Physics-Electrostatics I-72294.png
Electric charges q, q,–2q are placed at the corners of an equilateral triangle ABC of side l. The magnitude of electric dipole moments of the system is

  • Physics-Electrostatics I-72296.png
  • 2)
    Physics-Electrostatics I-72297.png

  • Physics-Electrostatics I-72298.png

  • Physics-Electrostatics I-72299.png

Physics-Electrostatics I-72301.png

  • Physics-Electrostatics I-72302.png
  • 2)
    Physics-Electrostatics I-72303.png
  • Zero

  • Physics-Electrostatics I-72304.png
Two opposite and equal charges 4 × 10–8 coulomb when placed 2 × 102 cm away, form a dipole. If dipole is placed in an external electric field 4 × 108 newton/coulomb, the value of maximum torque and the work done in rotating it through 180° will be
  • 64 × 10–4 Nm and 64 × 10–4 J
  • 32 × 10–4 Nm and 32 × 10–4 J
  • 64 × 10–4 Nm and 32 × 10–4 J
  • 32 × 10–4 Nm and 64 × 10–4 J
If Eα be the electric field strength of a short dipole at a point on its axial line and Ee that on the equatorial line at the same distance, then
  • Ee = 2Eα
  • Eα =2Ee
  • Eα = Ee
  • None of these
An electric dipole is placed in an electric field generated by point charge
  • The net electric force on the dipole must be zero
  • The net electric force on the dipole may be zero
  • The torque on the dipole due to the field must be zero
  • The torque on the dipole due to the field may be zero
A point Q lies on the perpendicular bisector of an electrical dipole of dipole moment p. If the distance of Q from the dipole is r (much larger than the size of the dipole), then electric field at Q is proportional to
  • p–1 and r–2
  • p and r–2
  • p2 and r–3
  • p and r–3
The electric intensity due to a 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, is
  • 6.25 × 107 N/C
  • 9.28 × 107 N/C
  • 13.1 × 1111 N/C
  • 20.5 × 107 N/C
Electric potential at an equatorial point of a small dipole with dipole moment P (r, distance from the dipole) is
  • Zero
  • 2)
    Physics-Electrostatics I-72313.png

  • Physics-Electrostatics I-72314.png

  • Physics-Electrostatics I-72315.png
The distance between H+ and Cl– ions in HCl molecule is 1.28 Å. What will be the potential due to this dipole ata distance of 12 Åon the axis of dipole
  • 0.13 V
  • 1.3 V
  • 13 V
  • 130 V
The potential at a point due to an electric dipole will be maximum and minimum when the angles between the axis of the dipole and the line joining the point to thedipole are respectively
  • 90° and 180°
  • 0° and 90°
  • 90° and 0°
  • 0° and 180°
The value of electric potential at any point due to any electric dipole is

  • Physics-Electrostatics I-72318.png
  • 2)
    Physics-Electrostatics I-72319.png

  • Physics-Electrostatics I-72320.png

  • Physics-Electrostatics I-72321.png
An electric dipole has the magnitude of its charge q and its dipole moment is p. It is placed in a uniform electric field E. If its dipole moment is along the direction of the field, the force on it and its potential energy are respectively
  • 2q. E and minimum
  • q. E and p. E
  • Zero and minimum
  • q. E and maximum
What is the angle between the electric dipole moment and the electric field strength due to it on the equatorial line?
  • 0°
  • 90°
  • 180°
  • None of these
For a dipole q = 2 × 10–6 C and d = 0.01 m. Calculate the maximum torque for this dipole if E = 5 × 105 N/C
  • 1 × 10–3 Nm–1
  • 10 × 10–3 Nm–1
  • 10 × 10–3 Nm
  • 1 × 102 Nm2
Two charge +3.2 × 10–19 C and –3.2 × 10–9 C kept 2.4 Å apart forms a dipole. If it is kept in uniformelectric field of intensity 4 × 105 volt/m then what willbe its electrical energy in equilibrium
  • +3 × 10–23 J
  • –3 × 10–23 J
  • –6 × 10–23 J
  • –2 × 10–23 J
Three point charges + q, –2q and + q are placed at points (x = 0, y = a, z = 0), (x = 0, y = 0, z =and (x = a, y = 0, z =respectively. The magnitude and direction of the electric dipole moment vector of this charge assembly are

  • Physics-Electrostatics I-72326.png
  • 2)
    Physics-Electrostatics I-72327.png

  • Physics-Electrostatics I-72328.png

  • Physics-Electrostatics I-72329.png

Physics-Electrostatics I-72331.png
  • Along the equatorial line towards the dipole
  • Along equatorial line away from the dipole

  • Physics-Electrostatics I-72332.png

  • Physics-Electrostatics I-72333.png

  • Physics-Electrostatics I-72334.png
A water molecule has an electric dipole moment 6.4 × 10–30 cm when it is in vapor state.The distance in metre between the centre of positive and negativecharge of the molecule is
  • 4 × 10–10
  • 4 × 10–11
  • 4 × 10–12
  • 4 × 10–13
The electric dipole moment of an electron and a proton 4.3 nm apart is
  • 6.88 × 10–28cm
  • 2.56 × 10–29 c2/m
  • 3.72 × 10–14 c/m
  • 11 × 10–46 c2/ m

Physics-Electrostatics I-72337.png
  • (i), (ii) and (iii) are correct
  • (i) and (iii) are correct and (ii) is wrong
  • Only (i) is correct
  • (i) and (ii) are correct (iii) is wrong
  • (i), (ii) and (iii) are wrong

Physics-Electrostatics I-72339.png
  • S2, S3 and S4
  • S3 and S4
  • S2 and S3
  • All four
An electric dipole of moment `p\' is placed in an electric field of intensity \'E\'. The dipole acquires a position such that the axis of the dipole makes an angle θ with the direction of the field. Assuming that the potential energy of the dipole to be zero when θ = 90°, the torque and the potential energy of the dipole will respectively be
  • pEsin θ, –pEcos θ
  • pEsin θ,–2pE cos θ
  • pEsin θ, 2pE cos θ
  • pEcos θ, –pEcos θ
A cylinder of radius R and length L is placed in a uniform electric field E parallel to the cylinder axis. The total flux for the surface of the cylinder is given by
  • 2πR2E
  • πR2/E
  • (πR2/πR)/ E
  • Zero
An electric charge q is placed at the centre of a cube of side a. The electric flux on one of its faces will be

  • Physics-Electrostatics I-72343.png
  • 2)
    Physics-Electrostatics I-72344.png

  • Physics-Electrostatics I-72345.png

  • Physics-Electrostatics I-72346.png

Physics-Electrostatics I-72348.png
  • Zero
  • 2)
    Physics-Electrostatics I-72349.png

  • Physics-Electrostatics I-72350.png

  • Physics-Electrostatics I-72351.png
Eight dipoles of charges of magnitude e are placed inside a cube. The total electric flux coming out of the cube will be

  • Physics-Electrostatics I-72353.png
  • 2)
    Physics-Electrostatics I-72354.png

  • Physics-Electrostatics I-72355.png
  • Zero
The inward and outward electric flux for a closed surface in units of N–m2/C are respectively 8 × 103 and 4 × 103. Then the total charge inside the surface is [where ɛ0= permitivity constant]
  • 4 × 103 C
  • –4 × 103 C

  • Physics-Electrostatics I-72364.png
  • –4 × 103 ɛ0 C
The electric intensity due to an infinite cylinder of radius R and having charge q per unit length at a distance r(r >R) from its axis is
  • Directly proportional to r2
  • Directly proportional to r3
  • Inversely proportional to r
  • Inversely proportional to r2
Shown below is a distribution of charges. The flux of electric field due to these charges through the surface S is
Physics-Electrostatics I-72367.png
  • 3q/ɛ0
  • 2q/ɛ0
  • q/ɛ0
  • Zero
Gauss\'s law is true only if force due to a charge varies as
  • r–1
  • r–2
  • r–3
  • r–4
An electric dipole is put in north-south direction in a sphere filled with water. Which statement is correct
  • Electric flux is coming towards sphere
  • Electric flux is coming out of sphere
  • Electric flux entering into sphere and leaving the sphere are same
  • Water does not permit electric flux to enter into sphere
A hollow cylinder has a charge q coulomb within it. If ɸ is the electric flux in units of volt – metre associated with the curved surface B, the flux linked with the plane surface Ain units of volt – metre will be
Physics-Electrostatics I-72369.png

  • Physics-Electrostatics I-72370.png
  • 2)
    Physics-Electrostatics I-72371.png

  • Physics-Electrostatics I-72372.png

  • Physics-Electrostatics I-72373.png

Physics-Electrostatics I-72375.png
  • Zero
  • EL2
  • EL2/(2ɛ0)
  • EL2/2
The adjacent diagram shows a charge +Q held on an insulating support S and enclosed by a hollow spherical conductor. Orepresents the centre of the spherical conductor and P is a point such that OP = x and SP = r.The electric field at point P will be
Physics-Electrostatics I-72377.png

  • Physics-Electrostatics I-72378.png
  • 2)
    Physics-Electrostatics I-72379.png
  • 0
  • None of these
The total electric flux through a cube when a charge 8q is placed at one corner of the cube is

  • Physics-Electrostatics I-72381.png
  • 2)
    Physics-Electrostatics I-72382.png

  • Physics-Electrostatics I-72383.png

  • Physics-Electrostatics I-72384.png

  • Physics-Electrostatics I-72385.png
Gauss\'s law is valid for
  • Any closed surface
  • Only regular close surfaces
  • Any open surface
  • Only irregular open surfaces
Gauss law of gravitation is

  • Physics-Electrostatics I-72387.png
  • 2)
    Physics-Electrostatics I-72388.png

  • Physics-Electrostatics I-72389.png
  • All of these
Charge motion within the Gaussian surface gives changing physical quantity
  • Electric field
  • Electric flux
  • Charge
  • Gaussian surface area
The angle subtended by a circular disk of diameter 2 cm at a distance 1000 cm form your eye is
  • 0.2°
  • 0.002°
  • 0.11°
  • 0.22°
Gauss\'s law of electrostatic would be invalid if
  • There were magnetic monopoles
  • The speed of light was not a universal constant
  • The inverse square law was not exactly true
  • The electrical charge was not quantized
A charge Q is enclosed by a Gaussian spherical surface of radius R. If the radius is doubled, then the outward electric flux will
  • Be doubled
  • Increase four times
  • Be reduced to half
  • Remain the same
What is the flux through a cube of side \'a\' if a point charge of q is at one of its corner?

  • Physics-Electrostatics I-72392.png
  • 2)
    Physics-Electrostatics I-72393.png

  • Physics-Electrostatics I-72394.png

  • Physics-Electrostatics I-72395.png
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