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Electromagnetics 1.Magnetic field is produced by a) stationary charge b) moving charge c) both stationary and moving charge d) none of the mentioned 2.The unit of electric field intensity is a) Tesla b) V/m c) N/Cd) not defined 3.Magnetic force on a electric charge is zero when a) only when charge is at rest b) only when charge is moving parallel to field c) when charge is at rest or when is moving parallel to field. d) not defined 4.The work done by the static electric field around a closed path a) always positive b) always zero c) always negative d) not defined

5.Curl of a uniform electric field is a) not defined b) zero c) always negative d) positive 6.Electric potential at a given point due to a electric dipole is inversely proportional to a) the distance b) the square of the distance c) product of charges d) the cube of distance 7.Displacement current is due to a)time varying electric field b)time varying magnetic field. c)constant magnetic field d)the cube of distance 8.The unit of electric dipole moment is a) Ampere-meter b) Coulomb-meter c) Tesla d) the cube of distance

9.Impedance of free space is a) zero b) 100 ohm c) 377 ohmd) the cube of distance 10.Vortex electric field is produced by a) Time varying magnetic fieldb) Time varying electric field c) constant magnetic field d) constant electric field 11.Faraday’s law states that the induced EMF is a)Proportional to the change in magnetic flux linkage. b)Equal to the negative rate of change of magnetic flux linkage with respect to time c)Equal to the negative change in magnetic flux linkage d)Equal to the change of magnetic flux 12.Two thin parallel wire carrying currents along the same direction. The force expe-rienced by one due to the other is a) Parallel to the lines. b) Perpendicular to the lines and attractive. c) Perpendicular to the lines and repulsive. d) Equal to the change of magnetic flux

13.For an electromagnetic wave, the direction of vector cross product of electric and magnetic field gives the direction of a)electric field. b)magnetic field. c)phase velocity d)Equal to the change of magnetic flux 14.The force between the two charges is F Newnons. When the distance between the two charges is doubled, the force is a)F/4 b)4F c)F/2 d)2F 15.The electric field line and equipotential surfaces are a) always parallel. b) inclined at any angle. c) always at 45 degree. d) always at 90 degree. 16.A sheet of mica is inserted between the plates of a parallel plate capacitor, then the capacitance will a) decrease b) become zero c) increase d) remain same

17.When a conductor is placed in external electric field, the field inside the conductor is a) less than external field. b) more than external field c) zerod) remain same 18.When a dielectric material is kept in external electric field, the field inside the dielectric is a) less than the external fieldb) more than the external field c) zero d) remain same 19.The unit of relative permittivity a)Farad-meter b)Farad/meter c)Farad d)it is dimensionless. 20.The material that can be used for shelding or screening the magnetic field is a) plastic b) mica c) wood d) copper 21.A point is represented in Cartesian coordinate as P(2,6,3),the radial component ρ in cylindrical coordinate will be

a)less than r in spherical coordinates b)greater than r in spherical coordinates c)equal to r in spherical coordinates d)unrelated to r in spherical coordinates 22.By saying that the electrostatic field is conservative, we mean that a) it is curl of the scalar potential b) it is product of the scalar potential and distance c) it is sum of the scalar potential and distance d) it is gradient of the scalar potential 23.Stokes theorem relates a)surface integral and line integral b)surface integral and volume integral c)volume integral and contour integral d)line integral and volume integral 24. Under electrostatic equilibrium conditions where does the excess charges lie in a conductor? a)on the surface of the conductor b)only inside the conductor and not on surface. c)at the centre of the conductor d)outside the conductor 25. The electric potential difference between two points in a electric field is the

a)work done in moving unit charge between the two points. b)difference between the forces at the two points. c)change in momentum of charge between two points. d)work done in moving arbirary charge between the two points 26.Point charges 30nC,-20nCand 10nC are located at (-1,0,2),(0,0,0) and (1,5,-1), respectively. The total flux leaving a cube of side 6m centered at the origin is a)-20nVm b)10nVm c)20nVm d)zero 27.The electric flux density on a spherical surface of radius r=b is the same when a point charge Q located at the origin and in the second case when the charge Q uniformly distributed on surface r=a (a<b) a)yes b)No c)Not necessarily d)zero 28.Suppose a uniform electric field exists in the room in which you are working, such that the lines of force are horizontal and at right angles to one wall. As you walk toward the wall from which the lines of force emerge into the room, are you walking toward a)Points of higher potential b)Points of lower potential c)points of constant potential

d) It will be higher 29.When a potential difference is applied across human heart, its behaviour can be modeled as that of electric dipole. Abnormal hearts can be detected by mapping a)equipotential surfaces b)Points of lower potential c)Not necessarily d)It will be higher 30.Inside a hollow conducting sphere which is kept in a external electric field a) electric field is zerob) constant but non zero c) electric field increase d) electric field decrease 31.The magnetic flux density (B) and a vector magnetic potential (A) are related by a) B=▼ X Ab) electric flux lines c) electric fields d) B=▼A 32.Of the following,the incorrect relation is a)D=εE b)B=μH c)J=σE d)B=μE

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