Cada pergunta deste Quiz é cronometrada.
Which of the following gives materials in order of decreasing values of permeability ?
Cobalt, Nickel, Aluminium, Iron
Permalloy, Nickel, Air, Water
Silver, Copper, Aluminium, Iron
Pure iron, Silicon iron. Aluminium, Bismuth.
In electrical machines the material preferred for pole shoes of electro-magnets is
Pure iron
Aluminium
Copper
Lead.
If the resistivity of aluminium is 0.0283 x 10-6 Ω-m, the resistivity of copper could be
0.017 x 10-5 Ω-m
0.0382 x 10-5 Ω-m
0.0832 x 10-6 Ω-m
0.0889 x 10-6 Ω-m
Three moving iron type voltmeters are connected as shown below. Voltmeter readings are V, V and V 1 2 as indicated. The correct relation among the voltmeter readings is
The input impedance of the permanent magnet moving coil (PMMC) voltmeter is infinite. Assuming that the diode shown in the figure below is ideal, the reading of the voltmeter in Volts is
4.46
3.15
2.23
0
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