Model Quiz - Magnetism and Electromagnetism Test2

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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 _____.
meter is surrounded by strong magnetic fields	a soft iron shielding is used
a plastic shielding is provided	a shielding of anon-magnetic material is used

2. Reciprocal of permeability is ______.
reluctivity	susceptibility
permittivity	conductance

3. The relative permeability is less than unity is case of _______.
ferromagnetic materials	ferrites
non-ferrous materials	diamagnetic materials

4. Which of the following is the unit of magnetic flux density ?
weber	lumens
tesla	none of the above

5. The magnetism left in the iron after exciting field has been removed is known as ______.
permeance	residual magnetism
susceptance	reluctance

6. Which of the following is not a unit of flux?
Maxwell	Telsa
Weber	All of the above

7. Which of the following is expected to have the maximum permeability ?
Brass	Copper
Zinc	Ebonite

8. One telsa is equal to ______.
1 Wb/mm2	1 Wb/m
1 Wb/m2	1 mWb/m2

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

10. When a magnet is in motion relative to a coil the induced e.m.f. does not depend upon ______.
resistance of the coil	motion of the magnet
number of turns of the coil	pole strength of the magnet

11. When two ends of a circular uniform wire are joined to the terminals of a battery, the field at the centre of the circle ______.
will be zero	will be infinite
will depend on the amount of e.m.f. applied	will depend on the radius of the circle

12. Susceptibility is positive for _______.
non-magnetic substances	diamagnetic substances
ferromagnetic substances	none of the above

13. Two long parallel conductors carry 100 A. If the conductors are separated by 20 mm, the force per metre of length of each conductor will be _____.
100 N	10 N
1 N	0.1 N

14. A 300 mm long conductor is carrying a current of 10 A and is situated at right angles to a magnetic field having a flux density of 0.8 T ; the force on the conductor will be _____.
240 N	24 N
2.4 N	0.24 N

15. A 200 turn coil having an axial length of 30 mm and a radius of 10 mm is pivoted in a magnetic field having a flux density of 0.8 T. If the coil carries a current of 0.5 A, the torque acting on the coil will be ______.
8 N-m	0.48 N-m
0.048 N-m	0.0048 N-m

16. 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 ?
2500 AT/m	250 AT/m
25 AT/m	2.5 AT/m

17. What is the magnitude and the direction of force per 1.1m length of a pair of conductors of a direct current linecarrying 10 amperes and spaced 100 mm apart ?
22 x 10"8 N	22 x 10"7 N
22 x 10-6 N	22 x 10"5 N

18. A square cross-sectional magnet has a pole strength of 1 x 10 Wb and cross sectional area of 20 mm x 20 mm. What is the strength at a distance of 100 mm from the unit pole in air ?
63.38 N/Wb	633.8 N/Wb
6338 N/Wb	63380 N/Wb

19. The unit of flux is the same as that of ______.
reluctance	resistance
permeance	pole strength

20. Unit for quantity of electricity is ______.
ampere-hour	watt
joule	coulomb