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CBSE Questions for Class 12 Medical Physics Electric Charges And Fields Quiz 10 - MCQExams.com

Which charge is not possible
  • 4.8×1016C
  • 8.0×1017C
  • 11.2×1017C
  • 12.0×1020C
A point charge Q is placed at the centre of a circular wire of radius R having charge q. The force of electrostatic interaction between point charge and the wire is:
1311019_b26f7a3bf6644b7a8d61aba941a10efd.png
  • qQ4πεoR2
  • q4πεoR
  • Zero
  • none of these
The tangent at any point of  field line gives the direction of
  • Electric field at that point
  • Electric force on positive charge at that point
  • Both (1) & (2)
  • Rotation of charge
Under the influence of the Coulomb field of charge +Q, a charge q is moving around it in an elliptical orbit. Find out the correct statements.
  • The angular momentum of the charge q is constant.
  • The linear momentum of the charge q is constant.
  • The angular velocity of the charge q is constant.
  • The linear speed of the charge q is constant.
Five positively charged particles are kept fixed on the x-axis at point (1m,0)(2m,0),(3m0)(4m0) and (5m0). The magnitude of charges kept at these points are 1μC,4μC,9μC,16μC, and 25μC respectively. The magnitude of net electric force on charge 1μC placed at origin is  
  • 4.5×103N
  • 4.5×102N
  • 4.5×102N
  • 4.5×104N
A charge Q is placed a the corner of a cube. The electric flux through all the six faces of the tube is 
  • Qε0
  • Q6ε0
  • Q8ε0
  • Q3ε0
The SI unit of electric flux is 
  • Voltmetre
  • Joule/Metre
  • Newton
  • None
A hollow cylinder has a charge q coulomb within it. If f the electric flux in units of volmeter associated with the curved surface B , the flx linked with the plane surface A in units of V-m will be :

1340015_ed82ace225f84713846ee366cd22759d.png
  • q2ε0
  • Φ3
  • qε0
  • 4qε0
In the hydrogen atom the electron moves around the proton with a speed of 2.0×106ms1 in a circular orbit of radius 5.0×1011 What is the equivalent dipole moment ?
  • 2×1024Am2
  • 4×1024Am2
  • 8×1024Am2
  • 16×1024Am2
A and B are two points on the axis and the perpendicular bisector respectively of an electric dipole. A and B are far away from the dipole and at equal distances from its centre. The fields at A and B i.e. EAandEB are respectively such that
  • EA=EB
  • EA=2EB
  • EA=2EB
  • EA=12EB
Figure shows two equipotential surface V1 and V2 . The component of electric field in x and y direction will be


1392881_bb66f16e63ca4c58b53bd0fcc4a0357e.png
  • Exi and Exj
  • Exi and Exj
  • Exi and Exj
  • Exi and Exj
An electric field E=(25ˆi+30ˆj)NC1 exists in a region of space. If the potential at the origin is taken to be zero then potential at X = 2m,y = 2 m is 
  • - 110 V
  • - 140 V
  • - 120 V
  • - 130 V
When a test charge is brought in from infinity along the perpendicular bisector of an electric dipole ,the work done is 
  • positive
  • Zero
  • Negative
  • None of theses
An electric charge produces an electric intensity of 500N/C at a point in air. If the air is replaced by a medium of dielectric constant 2.5, then the intensity of the electric field due to the same charge at the same point will be:
  • 100N/C
  • 150N/C
  • 200N/C
  • 300N/C

The magnetic induction field at the centre C of
the wire which is in the shape as shown in figure carrying current i is

  • μoi4πr(1+π)
  • μoi2πr(1+π)
  • μoiπr(1+π)
  • μoir(1+π)
The force of attraction between two charges 8μC and 0.2N. Find the distance of separation.
  • 412 meter
  • 1.2 meter
  • 120 meter
  • 0.12 meter
Determine the electric dipole moment of the system of three charges,placed on the vertices of an equilateral triangle ,as shown in the figure:
1333326_b13730933efa41b68c02d31f0991ca5a.png
  • (ql)ˆi+ˆj2
  • 3qlˆjˆi2
  • 3qlˆj
  • 2qlˆj
Which potential graph describes the electric field shown ? 
1339188_f8ada76d485642d2841e3bb49eb50af5.png
The electric flux over the surface of a sphere if it is charged with 10μC is 
  • 36π×104Nm2/C
  • 36π×104Nm2/C
  • 36π×106Nm2/C
  • 36π×106Nm2/C
A charge is placed at the edge of a cube of each side a. Calculate the electric flux through each face of the cube.
  • Q4e0
  • Q24e0
  • Q2e0
  • Q15e0
Force of attraction between two point charges Q and Q separated by d meter is Fe. When these charges are placed two identical sphere of radius R=0.3 d whose centries are d meter apart the force of attraction between them is 
  • Greater than Fe
  • Equal to Fe
  • Less than Fe
  • None of these
A system of charge as shown in figure.  The magnitude net electric dipole moment of the system of charges will be 
1416399_2c0eb1ff1be74e0b97fd5eb22d97584f.PNG
  • 2ql
  • 4ql
  • 3ql
  • zero
An electric dipole is situated in an electric field of uniform intensity E whose dipole moment is p and moment of inertia is I. if the dipole is displaced then the angular frequency of its oscillation is
  • (pEI)1/2
  • (pEI)3/2
  • (IpE)1/2
  • (pIE)1/2
An electric dipole of moment P is placed along the lines of force of electric field E and is in equilibrium. the work done in deflecting it through an angle of 1800 is equal to-
  • PE
  • +2PE
  • 2PE
  • ZERO
Which of the following is not a unit of charge ?
  • coulomb
  • ampere-second
  • microcoulomb
  • ampere/second
The field potential inside a charged ball of radius R and centre at o depends only on distance from its center as V(r)=αr2+β when α,β are +ve constant. now choose correct options
  • electric field inside the ball Er=2αr
  • electric flux passing through an imaginary sphere of radius r centre at O will be 2παr4
  • volume charge density p(r) inside ball is 6ε0α
  • electric energy of charged ball will be 485πε0α2R5
A problem of practical interest is to make a beam of electrons turn at 90 corner. This can be done with the parallel plates shown in figure. An electron with kinetic energy 8.0×1017J enters through a small hole in the bottom plate. The strength of electric field that is needed if the electron is to emerge from an exit hole 1.0 cm away from the entrance hole, traveling at right angles to its original direction is _______ ×105N/C.
1374849_1fbd5cd8403d4feb81de5a5cc15442f2.jpg
  • 3
  • 1
  • 6
  • 2.5

A soap bubble is given a negative charge, then its radius  

  • Decreasing
  • Increasing
  • Remains unchanged
  • Nothing can be predicated as information is insufficient
For the following electric field lines electric field is 
1448122_6d53877f363b4f69ad0cbe8b8501d526.JPG
  • Non uniform
  • uniform
  • Both uniform & non uniform
  • can't be said
An electric field exists in the space between two charged metal plates.
which graph shows the variation of electric field strenth E with distance d from X along the line XY ?
1404294_5b548e744a6b47f4950d03e5e46d9e13.PNG
(i) Obtain the expression for the torque r experienced by an electric dipole of dipole moment p in a uniform electric field, E (ii) what will happen if the field were not uniform? state the condition under which the dipole is in
  • stable equilibrium
  • unstable equilibrium
  • electric dipole
  • magnetic dipole
In the given figure, electric lines of force diagram is shown. Then:
1432768_7008014b6a994b6ea6a49c65cde1d820.png
  • EA<EB
  • EA>EB>EC
  • EC>EB
  • EA=EB=EC
The flux through the hemispherical surface in the figure shown below is
1389961_548a74d09ca3437ea577a82d7114f3de.PNG
  • πR2E
  • 2πR2E
  • πRE
  • Zero
There are three concentric thin sphere of radius a, b, c ( a > b > c ) . the total surface charges densities on their surfaces are σ,σ, sigma respectively. the magnitude of electric field at r ( distance from centre ) such that a > r > b is :
  • 0
  • σε0r2(b2c2)
  • σε0r2(a2+b2)
  • none of these
An infinite large sheet has charge density σC/m2. Find electric field at a distance d perpendicular to the sheet.
  • E=σ2ε0
  • E=σε0
  • E=2σε0
  • None of these
A charged oil drop is suspended in a uniform field of 3 x 104  v/m so that it neither falls nor rises. The charge on the drop will (Take the mass of the charge  = 9.9 x 10-15 kg  and g = 10 m/s2  )
  • 3.3×1018N/C
  • 2.25×1010N/C
  • 5×1010N/C
  • None
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
  • (2ˆi+3ˆj+ˆk)
  • (6ˆi+9ˆj+ˆk)
  • (3ˆi+5ˆj+3ˆk)
  • (6ˆi+5ˆj+2ˆk)
Two charges q and q placed at (a,0) and (a,0) on the x-axis. Another charge 2q is taken from (0,0) to (0,a), then the work done to do so 
  • q2πε0a
  • q4πε0a
  • Zero
  • Infinite
Which of the following is false for electric lines of force ?
  • They always start from positive charges and terminate on negative charges
  • They are always perpendicular to the surface of a charged conductors
  • They always form closed loops
  • They are parallel and equally spaced in a region of uniform electric field
If the surface normal vector ˆn makes an angle θ withthe electric field E , then the electric flux through asurface of area dS is given by
  • ϕ=EdSsinθ
  • ϕ=EdScosθ
  • ϕ=dScosθ
  • ϕ=Ecosθ
When 1014 electrons are removed from a neutral metal sphere, the charges on the sphere become 
  • 16μC
  • 16μC
  • 32μC
  • 32μC
Three charges +2q,q and q are placed at pooul A (a,0),B(a,a) and C(a, a) respectively in x2y plane. The magnitude of net electric dipole moment of the system will be
  • 11qa
  • q
  • 3qa
  • 4qa

What is the Coulomb's force between two αparticles separated by a distance of 3.2×1015m

  • 90N
  • 45N
  • 60N
  • 75N
in which case charges would be produce???
  • A plastic ruler is rubbed vigorously with a woollen cloth.
  • A glass rod rubbed with a piece of silk is brought near a negatively charged paper cylinder.
  • A positively charged rod is moved slowly towards an uncharged paper cylinder, which is suspended by a string, until the rod touches the cylinder.
  • all of these.
A dipole is placed in a uniform electric field with its axis parallel to the field. It experiences :
  • both a net force and torque
  • only a net force
  • neither a net force nor a torque
  • only a torque
In Region of Electric field Given by E=(Ax+B)ˆi. Where A=20 unit and B=10 unit. If Electric potential at x=1m is V1 and at x=5m is V2. Then V1V2 is equal to
  • 150V
  • 170V
  • 140V
  • 180V
Which of the following charges can from an electric dipole ?
  • +1μC,1mC
  • +1×103mC,1μC
  • +5×103C,2×103C
  • 1C,1C
Electric lines of forces.
  • May form closed path
  • Must form closed path
  • May be discontinuous
  • Both (a) and (c) are correct
The electric intensity at a point A at distance x from uniformly charged non-conducting plane is E. Then
  • The electric charge per unit area on the plane is 2εE
  • Magnitude E/2 of field is due to the charges at points within distance 2x from the point A
  • Magnitude E of field is due to the charges at points within distance 2x from point A
  • Both (a) and (c) are correct
Two positive charges and an negative charge, all of equal magnitude, are set at the corners of an equilateral triangle.
Which diagram best represents the electric field surrounding the charges?
0:0:3


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Practice Class 12 Medical Physics Quiz Questions and Answers