162. Indicate which of the following material does not retain magnetism permanently.
A. Soft iron
B. Stainless steel
C. Hardened steel
D. None of the above

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163. The main constituent of perm-alloy is
A. cobalt
B. chromium
C. nickel
D. tungsten

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164. The use of permanent magnets is not made in
A. magnetoys
B. transformers
C.anteena
D.material

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165. Paramagnetic permeability
A. slightly less than unity
B. equal to unity
C. slightly more than unity
D. equal to that ferromagnetic materials

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166. Two infinitely long parallel conductors in vacuum and separated 1 metre between centres when a current of materials have relative of 100 produce on each other a force of
A. 2 x 10-2 N/m
B. 2 x 10-3 N/m
C. 2 x 10-5 N/m
D. 2 x 10-7 N/m

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167. Which of the following is a ferromagnetic material?
A. Tungsten
B. Aluminium
C. Copper
D. Nickel

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168. Gilbert is a unit of
A. electromotive force
B. magnetomotive force
C. conductance
D. permittivity

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