Electromagnetic Fields Objective Questions
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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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The heating time constant of an electrical machine gives an induction of its
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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 developed electromagnetic force and or torque in electromechanical energy conversion system act in a direction that tends
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The right hand rule for determining the direction of the induced EMF was introduced by
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An open coil has
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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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In an inductor current cannot change abruptly. Comment on the statement.
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The main purpose of choke is
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A crack in the magnetic path of an inductor will result in
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Conductor is constant and field is varying then emf will induce. This principle is called
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For a linear electromagnetic circuit, which of the following statement is true?
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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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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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The effective reactance of an inductive coil
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Which of following is the unit of inductance?
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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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Two combination of similar inductors are show below. Which one has more inductance between A and B?
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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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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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RF inductors are characterized by
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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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Conductor is constant and field is varying then emf will induce. This principle is called
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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 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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Conductor is varying and field is fixed then emf will induces. This principle is called
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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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If the resistance of a conductor does not vary in accordance with the Ohms law it is known as
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The operation of electric generators and motors depend on the intraction between magnetic field and
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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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For DC voltage an inductor is virtually a
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Which of following is true for a purely inductive circuit ?
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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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For an inductor, current is proportional to
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