100 Important Magnetism and Electromagnetism MCQ Question and Answer | PDF Free Download
1.The magneto-motive force is
- AThe voltage across the two ends of exciting coil
- BThe flow of an electric current
- CThe sum of all currents embraced by one line of magnetic field
- DThe passage of magnetic field through an exciting coil
2.What will be the current passing through the ring shaped air cored coil when numbers of turns is 800 and amperes turns are 3200
- A2
- B4
- C6
- D8
3.What will be the magnetic potential difference across the air gap of 2 cm length in magnetic field of 200 AT/m?
- A2 AT
- B4 AT
- C6 AT
- D10 AT
4.Which of the following statements is correct ?
- AThe magnetic flux inside an exciting coil is lower than its outside surface
- BThe magnetic flux inside an exciting coil is zero
- CThe magnetic flux inside an exciting coil is greater than its outside surface
- DThe magnetic flux inside an exciting coil is same as on its outside surface
5.A certain amount of current flows through a ring shaped coil with fixed numbers of turns. How does the magnetic induction B varies inside the coil if an iron core is threaded into coil without dimensional change of coil?
- ADecrease
- BIncreases
- CRemain same
- DFirst increases and then decreases depending on the depth of iron insertion
6.The magnetic reluctance of material
- ADecrease with increasing cross-sectional area of material
- BIncreases with increasing cross-sectional area of material
- CDoes not vary with increasing cross-sectional area of material
- DAny of the above
7.The initial permeability of an iron rod is
- AThe highest permeability of the iron rod
- BThe lowest permeability of the iron rod
- CThe permeability at the end of the iron rod
- DThe permeability almost in non-magnetised state
8.Which part of the magnetic path requires largest m.m.f?
- AAir gap
- BCoil
- CInductance
- DCore
9.How does the magnetic compass needle behave in a magnetic field?
- AIt assures a position right angle to magnetic field
- BIt starts rotating
- CIt assures a position which follows a line of magnetic field
- DNone of the above
10.The strength of magnetic flux in a simple magnetic field
- AIs constant and has same value in energy part of the magnetic field
- BIncreases continuously from initial value to final value
- CDecreases continuously from initial value to final value
- DFirst increases and then decreases till it becomes zero
11.The stray line of magnetic flux is defined as
- AA line vertical to the flux lines
- BThe mean length of a ring shaped coil
- CA line of magnetic flux in anon-uniform field
- DA line of magnetic flux which does not follow the designed path
12.The bar magnet has
- AThe dipole moment
- BMonopole moment
- C(a) and (b) both
- DNone of the above
13.Which of the following materials are diamagnetic?
- ASilver
- BCopper
- CSilver and copper
- DIron
14.Which of the following type of materials are not very important for engineering applications?
- AFerromagnetic
- BParamagnetic
- CDiamagnetic
- DNone of the above
15.Which of the following material has the highest saturation value?
- AFerromagnetic materials
- BParamagnetic materials
- CDiamagnetic materials
- DFerrites
16.The magnetic materials exhibit the property of magnetization because of
- ASpin of electrons
- BSpin of nucleus
- CSpin of nucleus
- DAll of the above
17.For which of the following materials the net magnetic moment should be zero?
- ADiamagnetic materials
- BFerromagnetic material
- CAntiferromagnetic materials
- DAntiferrimagnetic materials
18.The attraction capacity of electromagnet will increase if the
- ACore length increase
- BCore area increases
- CFlux density decreases
- DFlux density increases
19.Which of the following statement is correct?
- AThe conductivity of ferrites is better than ferromagnetic materials
- BThe conductivity of ferromagnetic material is better than ferrites
- CThe conductivity of ferrites is very high
- DThe conductivity of ferrites is same as that of ferromagnetic materials
20.The magnetization and applied field in ferromagnetic materials are related
- ASinusoidally
- BLinearly
- CNon-linearly
- DParabolically