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This set of Electromagnetics Multiple Choice Questions & Answers (MCQs) focuses on Electromagnetics Set 13
Q1 | The minimum value of potential gradient in a cable occurs in
- insulation
- conductor
- outer sheath
- uniformly all over
Q2 | Acharge which when placed in vacuum from an equal and similar charge repels with aforce of 9 x 10 N, is known as
- milli-coulomb
- micro-coulomb
- pico-coulomb
- coulomb
Q3 | Dielectric strength of a medium is usually expressed in
- j/mm
- c/m2
- kv/mm
- n/mm
Q4 | A positive and a negative charge are initially 50 mm apart. When they are moved closetogether so that they are now only 10 mm apart, the force between them will be
- 5 times smaller than before
- 5 times greater than before
- 10 times greater than before
- 25 times larger than before
Q5 | Which is the most superior dielectric out of the following ?
- air
- glass
- bakelite
- paper
Q6 | When a dielectric is placed in an electric field the field strength
- decreases
- increases
- reduces to zero
- remain unchanged
Q7 | To prevent the generation of static charges on rubber or flat leather
- surface is moistened
- conductive dressing is done
- oil compound dressing is done
- talcum powder is sprayed on the surface
Q8 | Which of the following capacitor is preferred in case of single phase motor ?
- mica capacitor
- paper capacitor
- electrolytic capacitor
- ceramic capacitor
Q9 | A capacitance is a circuit component that opposes the change in circuit
- current
- voltage
- impedance
- none of the above
Q10 | A condenser suitable for D.C. only is
- metallic plate variable gang condenser
- metallic paper capacitor
- oil impregrated paper condenser
- poled aluminium electrolytic condenser
Q11 | In a capacitor, the electric charge is stored in
- metal plates
- dielectric
- dielectric as well as metal plates
- none of the above
Q12 | Tesla is a unit of
- field strength
- inductance
- flux density
- flux
Q13 | The materials having low retentivity are suitable for making
- weak magnets
- temporary magnets
- permanent magnets
- none of the above
Q14 | A magnetic field exists around
- iron
- copper
- aluminium
- moving charges
Q15 | Ferrites are materials.
- paramagnetic
- diamagnetic
- ferromagnetic
- none of the above
Q16 | Air gap has eluctance as compared to iron or steel path
- little
- lower
- higher
- zero
Q17 | The direction of magnetic lines of force is
- from south pole to north pole
- from north pole to south pole
- from one end of the magnet to another
- none of the above
Q18 | Which of the following is a vector quantity ?
- relative permeability
- magnetic field intensity
- flux density
- magnetic potential
Q19 | The two conductors of a transmission line carry equal current I in opposite directions.The force on each conductor is
- proportional to 7
- proportional to x
- proportional to distance between the conductors
- inversely proportional to i
Q20 | A material which is slightly repelled by a magnetic field is known as
- ferromagnetic material
- diamagnetic material
- paramag>etic material
- conducting material
Q21 | When an iron piece is placed in a magnetic field
- the magnetic lines of force will bend away from their usual paths in order to go away from the piece
- the magnetic lines of force will bend away from their usual paths in order to pass through the piece
- the magnetic field will not be affected
- the iron piece will break
Q22 | Fleming's left hand rule is used to find
- direction of magnetic field due to current carrying conductor
- direction of flux in a solenoid
- direction of force on a current car¬rying conductor in a magnetic field
- polarity of a magnetic pole
Q23 | The ratio of intensity of magnetisation to the magnetisation force is known as
- flux density
- susceptibility
- relative permeability
- none of the above
Q24 | The left hand rule correlates to
- current, induced e.m.f. and direc¬tion of force on a conductor
- magnetic field, electric field and direction of force on a conductor
- self induction, mutual induction and direction of force on a conductor
- current, magnetic field and direc¬tion of force on a conductor
Q25 | The unit of relative permeability is
- henry/metre
- henry
- henry/sq. m
- it is dimensionless