Electromagnetic Fields Objective Questions
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Magnetic circuit with cross sectional area of 20 cm^{2} is to be operated at 50 Hz from 120 V_{rms} supply. The number of turns required to active a peak magnetic flux density of 1.8 T in the core flux is
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Whenever the magnetic flux changes with respect to an electric conductor or a coil, an EMF is induced in the conductor is Faradayâ€™s
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A crack in the magnetic path of an inductor will result in
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A pure inductor when connected across 220 V, 50 Hz supply consumes 100 W. From the above statement it can be concluded that
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The heating time constant of an electrical machine gives an induction of its
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Conductor is constant and field is varying then emf will induce. This principle is called
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In an iron cored coil the iron core is removed so that the coil becomes an air core coil. The inductance of the coil will
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Flemings left hand rule may be applied to an electric generator to find out the direction of
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The energy stored in the magnetic field at a solenoid 30 cm long and 3 cm diameter wound with 1000 turns of wire carrying an current at 10 A, is
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The operation of electric generators and motors depend on the intraction between magnetic field and
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For an inductor, current is proportional to
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The electric flux is given D = (2y^{2} + z) I_{x} + 4xy I_{y} + x 1_{z} C/m^{2}. The volume charge density at point (1,0,3) is
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If an electric current carrying coil is placed in a uniform magnetic field direction of magnetic induction, then
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The core of coil length is 200 mm. The inductance of coil is 6 mH. If the core length is doubled, all other quantities, remaining the same, the inductance will be
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Which of following is true for a purely inductive circuit ?
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A fan blade of length 2R rotates in a time period T in a magnetic field B. The induced voltage in the blade in
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The coils having self inductance of 10 mH and 15 mH have an effective inductance of 40 mH, when connected in series aiding. What will be the equivalent inductance if we connect then in series opposing?
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In an inductor current cannot change abruptly. Comment on the statement.
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An open coil has
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The right hand rule for determining the direction of the induced EMF was introduced by
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The developed electromagnetic force and or torque in electromechanical energy conversion system act in a direction that tends
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Which of following is the unit of inductance?
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RF inductors are characterized by
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Two combination of similar inductors are show below. Which one has more inductance between A and B?
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The energy stored in the magnetic field at a solenoid 30 cm long and 3 cm diameter wound with 1000 turns of wire carrying an current at 10 A, is
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Conductor is constant and field is varying then emf will induce. This principle is called
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For DC voltage an inductor is virtually a
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For a linear electromagnetic circuit, which of the following statement is true?
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The two windings of a transformer have an inductor of 2 H each. If mutual inductor between them is also 2 H, then
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The total inductance of a 30 mH inductance (L_{1}) and a 60 mH inductance (L_{2}) if the inductance L_{1} and L_{2} in series aiding with 30 mH mutual inductance, then total inductance will be
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The effective reactance of an inductive coil
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If the resistance of a conductor does not vary in accordance with the Ohms law it is known as
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The main purpose of choke is
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The total inductance of a 30 mH inductance (L_{1}) and a 60 mH inductance (L_{2}) in parallel without mutual coupling will be
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Conductor is varying and field is fixed then emf will induces. This principle is called
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