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Moving Charges And Magnetism
Hysteresis loops for two magnetic materials A and B are given below:
These materials are used to make magnets for electric generators, transformer core and electromagnet core. Then it is proper to use:
A for electric generators and transformers.
A for electromagnets and B for electric generators
A for transformers and B for electric generators.
B for electromagnets and transformers.
D.
B for electromagnets and transformers.
Area of the hysteresis loop is proportional to the net energy absorbed per unit volume by the material, as it is taken over a complete cycle of magnetisation.
For electromagnets and transformers, energy loss should be low.
i.e thin hysteresis curves.
Also |B|→0 When H = 0 and |H| should be small when B →0.
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Two moving coil meters, M1 and M2 have the following particulars:
R1 = 10 Ω N1 = 30,
A1 = 3.6 x 10–3 m2, B1 = 0.25 T
R2 = 14 Ω; N2 = 42,
A2 = 1.8 x 10–3 m2, B2 = 0.50 T
(The spring constants k are identical for the two meters).
Determine the ratio of (a) current sensitivity and (b) voltage sensitivity of M2 and M1.
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