In low or standard frequency induction furnace, heat is produced by the (A) Combination of induced current and skin effect (B) Induction and resistance (C) Current flow through a heating element (D) None of these

In low or standard frequency induction furnace, heat is produced by
the
(A) Combination of induced current and skin effect
(B) Induction and resistance
(C) Current flow through a heating element
(D) None of these
by

1 Answer

Answer :

(B) Induction and resistance
by

Related questions

The electric furnace in which heat is produced by a combination of induced current and skin effect is called __________ furnace. (A) Arc(B) Resistance(C) Low frequency induction(D) High frequency induction

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Last Answer : (D) High frequency induction

The resistance furnace produces heat by the (A) Electric arc struck between electrodes and the charge (B) Flow of current through a heating element (C) Combination of induced current and skin effect (D) None of these

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Last Answer : (B) Flow of current through a heating element

An electric furnace producing heat by means of an electric arc struck between each of three electrodes and the charge is called __________ furnace. (A) Resistance (B) Arc (C) Low frequency induction (D) None of these

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In the heating process of the ________type a simple method of temperature control is possible by means of a special alloy which loses its magnetic properties at a particular high temperature and regains them when cooled to a temperature below this value. (A) Indirect induction over (B) core type induction furnace (C) coreless induction furnace (D) high frequency eddy current

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Last Answer : Ans: D Magnetic property of alloy changes with change of the temperature and Heat is produced due to eddy current = i2R and i α f2

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In a furnace with heating element temperature at 1700°C, the dominant mechanism of heat transfer will be (A) Conduction (B) Radiation (C) Natural convection (D) Forced convection

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Out of the following methods of heating the one which is independent of supply frequency is (A) electric arc heating (B) induction heating (C) electric resistance heating (D) dielectric heating

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Last Answer : (D) It erodes furnace walls

A capacitor and a coil are connected in series. The capacitor is charged and allowed to discharge through the coil. The current that will then flow through the capacitor-coil combination will do one of the following things. Will it: w) flow in one direction, beginning at a maximum and decreasing rapidly to zero x) oscillate indefinitely y) oscillate but diminish steadily to zero z) oscillate at high frequency at first but then at slower frequency

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In order that current should flow without causing excessive heating or voltage drop, the relay contacts should (a) have low contact resistance (b) be clean and smooth (c) be of sufficient size and proper shape (d) have all above properties

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An electric toaster uses nichrome for its heating element. When a negligibly small current passes through it. It resistance at room temperature `(27.0

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__________ furnace is not an electric furnace. (A) Arc (B) Induction (C) Pot (D) Resistance

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Slip of the induction machine is 0.02 and the stator supply frequency is 50 Hz. What will be the frequency of the rotor induced emf? (A) 10 Hz. (B) 50 Hz. (C) 1 Hz. (D) 2500 Hz.

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Last Answer : (D) All (A), (B) and (C)

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Which of the following is not applicable to liquid fuels? a) the viscosity of a liquid fuel is a measure of its internal resistance to flow. b) the viscosity of all liquid fuels decreases with increase in its temperature c) higher the viscosity of liquid fuels, higher will be its heating value d) viscous fuels need heat tracing

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The speed of a three-phase squirrel-cage induction-type motor operating in a fixed frequency system is varied by changing the _____________. A. number of phases to the motor B. number of stator poles C. locked rotor current D. resistance of the rotor winding

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Last Answer : Answer: B

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In a three-phase, squirrel-cage type, induction motor the rotating magnetic field is established by the _____________. A. current induced in the rotor windings B. application of a three-phase voltage supply to the stator windings C. laminated steel core and aluminum conductors in the rotor D. interaction of the magnetic field caused by the induced current in the squirrel-cage bars with the magnetic field of the stator

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Which one is not an induced draught furnace? (A) Blast furnace stove (B) Sintering furnace (C) High pressure boiler (D) None of these

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Last Answer : (C) Positive pressure exists in the furnace

Reversing the current flow through a coil will ___________. A. reduce the amount of flux produced B. have no effect on the eddy currents produced C. reduce the power consumed D. reverse its two-pole field

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Last Answer : Answer: D

A characteristic of an induction motor with a low resistance rotor winding is _____________. A. high starting voltage B. high starting current C. high slippage D. low starting voltage

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Furnace oil consumption in a furnace for a given duty employing preheated combination air (at 300°) may be reduced by about __________ percent as compared to the use of atmospheric combustion air. (A) 5 (B) 10 (C) 20 (D) 35

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Flue gas from the heating chamber of byproduct coke ovens is removed by (A) Forced draft fan (B) Induced draft fan (C) Steam ejector (D) Natural draft

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To limit the current flow through a DC voltmeter to as low a value as possible, the moving coil circuit is provided with a/an _____________. A. high series resistance B. high parallel resistance C. series inductor D. external shunt

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Last Answer : Answer: D

When troubleshooting electronic equipment, you should use a high impedance multimeter ________________. A. to prevent excess current flow through the meter that would damage it B. for AC measurements only and a low resistance meter for DC measurements C. whenever a low impedance meter is not available, regardless of the components being tested D. so as not to load down the circuit and obtain erroneous voltage readings

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Last Answer : Answer: D

Straight silicon steel (containing Si from 0.5 to 5%) because of their low hysteresis loss and high magnetic permeability are used for electrical appliances. Which of the following electrical appliances made of silicon steel contains maximum percentage of silicon (about 4%)? (A) Armature of small motors/generators (B) Generators and small motors (C) Induction motors (D) High frequency transformers

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Coke oven gas is a better fuel than blast furnace gas, because of its higher (A) Calorific value, cleanliness and relatively low distribution cost (due to its low specific gravity) (B) Adiabatic flame temperature (C) Heat release rate (thus requiring smaller combustion chamber) (D) All (A), (B) and (C)

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Specific heating capacity of a furnace is expressed as (A) Weight heated/hr (B) Weight heated/furnace volume (C) Weight heated/hr/furnace volume (D) None of these

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Last Answer : (C) Weight heated/hr/furnace volume

Thermal efficiency of blast furnace stoves used for heating blast (air) may be about __________ percent. (A) 20 (B) 40 (C) 60 (D) 80

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Last Answer : (D) 80