Electromagnetism Electrical Questions Answers - Set 06 - ObjectiveBooks

# Practice Test: Question Set - 06

1. The working of a meter is based on the use of a permanent magnet. In order to protect the meter functioning from stray magnetic fields
(A) Meter is surrounded by strong magnetic fields
(B) A soft iron shielding is used
(C) A plastic shielding is provided
(D) A shielding of anon-magnetic material is used

2. If the cross-sectional area of a magnetic field increases, but the flux remains the same, the flux density
(A) Increases
(B) Decreases
(C) Remains the same
(D) Doubles

3. Out of the following statements, concerning an electric field, which statement is not true?
(A) The electric intensity is a vector quantity
(B) The electric field intensity at a point is numerically equal to the force exerted upon a charge placed at that point
(C) An electric field is defined as a point in space at which an electric charge would experience a force
(D) Unit field intensity in the exertion of a force of one Newton on a charge of one coulomb

4. The induced voltage across a stationary conductor in a stationary magnetic field is
(A) Zero
(B) Reversed in polarity
(C) Increased
(D) Decreased

5. The electromagnet has 50 turns and a current of 1A flows through the coil. If the length of the magnet circuit is 200 mm, what is the magnetic field strength?
(A) 2500 AT/m
(B) 250 AT/m
(C) 25 AT/m
(D) 2.5 AT/m

6. The relative permeability of materials is not constant.
(A) Diamagnetic
(B) Paramagnetic
(C) Ferromagnetic
(D) Insulating

7. The tesla is the unit of magnetic flux.
(A) True
(B) False

8. What is the reluctance of a material that has a length of 0.07 m, a cross-sectional area of 0.014 m2, and a permeability of 4,500 μWb/At × m?
(A) 1111 At/Wb
(B) 111 At/Wb
(C) 11 At/Wb
(D) 1 At/Wb

9. The bar magnet has
(A) The dipole moment
(B) Monopole moment
(C) Both (A) and (B)
(D) None of the above

10. The magneto-motive force is
(A) The voltage across the two ends of exciting coil
(B) The flow of an electric current
(C) The sum of all currents embraced by one line of magnetic field
(D) The passage of magnetic field through an exciting coil

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