Heating and Welding Electrical Engineering MCQ Multiple Choice Questions. Prepare Top Interview Questions and Answers for Civil Engineering Interview Questions, Mechanical Engineering Interview Questions, Electrical Engineering Interview Questions, and Online preparation tests for Engineering Students. Latest Heating and Welding Questions and Answers
Which of the following is an advantage of heating by electricity?
a) High initial cost
b) High maintenance cost
c) High efficiency
d) Low safety
Answer: c) High efficiency
________ has the highest value of thermal conductivity.
a) Air
b) Water
c) Copper
d) Diamond
Answer: d) Diamond
Which of the following heating methods has the maximum power factor?
a) Induction heating
b) Electric arc heating
c) Resistance heating
d) Dielectric heating
Answer: c) Resistance heating
Which method has a leading power factor?
a) Capacitor start motor
b) Induction motor
c) Synchronous motor
d) Direct current motor
Answer: c) Synchronous motor
________ is used for heating non-conducting materials.
a) Induction heating
b) Resistance heating
c) Arc heating
d) Dielectric heating
Answer: d) Dielectric heating
Which of the following heating methods is not dependent on the frequency of supply?
a) Induction heating
b) Resistance heating
c) Arc heating
d) Dielectric heating
Answer: b) Resistance heating
When a body reflects the entire radiation incident on it, then it is known as ________.
a) White body
b) Gray body
c) Black body
d) Perfect body
Answer: c) Black body
For the transmission of heat from one body to another, ________ is required.
a) Temperature difference
b) Pressure difference
c) Density difference
d) Thermal conductivity
Answer: d) Thermal conductivity
Heat transfer by conduction will not occur when ________.
a) There is a temperature difference between two bodies
b) There is a medium between two bodies
c) Two bodies are in contact
d) Two bodies have different densities
Answer: b) There is a medium between two bodies
A perfect black body is one that ________.
a) Absorbs all radiation incidents on it
b) Reflects all radiation incidents on it
c) Transmits all radiation incidents on it
d) Absorbs, reflects, and transmits all radiation incidents on it
Answer: a) Absorbs all radiation incidents on it
Which of the following is not a mode of heat transfer?
a. Convection
b. Conduction
c. Radiation
d. Refraction
Answer: d. Refraction
What is the process of heat transfer during the reentry of satellites and missiles, at very high speeds, into the earth's atmosphere known as?
a. Convection
b. Radiation
c. Conduction
d. Adiabatic heating
Answer: b. Radiation
Which of the following has the highest value of thermal conductivity?
a. Air
b. Water
c. Copper
d. Glass
Answer: c. Copper
The induction heating process is based on which of the following principles?
a. Ohm's law
b. Faraday's law
c. Newton's law
d. Kepler's law
Answer: b. Faraday's law
Which of the following insulating materials is suitable for low-temperature applications?
a. Asbestos
b. Fiberglass
c. Mineral wool
d. Calcium silicate
Answer: d. Calcium silicate
A non-dimensional number generally associated with natural convection heat transfer is:
a. Peclet number
b. Nusselt number
c. Reynolds number
d. Fourier number
Answer: b. Nusselt number
The temperature inside a furnace is usually measured by which of the following?
a. Thermocouple
b. RTD (Resistance Temperature Detector)
c. Pyrometer
d. Manometer
Answer: c. Pyrometer
What will happen if the thickness of the refractory wall of the furnace is increased?
a. The efficiency of the furnace will increase
b. The efficiency of the furnace will decrease
c. The temperature inside the furnace will decrease
d. The temperature inside the furnace will increase
Answer: d. The temperature inside the furnace will increase
The material of the heating element for a furnace should have:
a. High melting point and low resistivity
b. Low melting point and low resistivity
c. High melting point and high resistivity
d. Low melting point and high resistivity
Answer: c. High melting point and high resistivity
In a resistance furnace, the atmosphere is:
a. Inert
b. Reducing
c. Oxidizing
d. Neutral
Answer: a. Inert
By which of the following methods can the temperature inside an arc furnace be varied?
a. By changing the arc length
b. By changing the voltage applied
c. By changing the current applied
d. By changing the composition of the charge
Answer: c. By changing the current applied
In induction heating, ______ is abnormally high.
a. Frequency
b. Voltage
c. Current
d. Resistance
Answer: c. Current
By the use of which of the following can a high-frequency power supply for induction furnaces be obtained?
a. Transformer
b. Rectifier
c. Inverter
d. Converter
Answer: c. Inverter
Induction furnaces are employed for which of the following?
a. Melting of metals
b. Heating of liquids
c. Boiling of gases
d. Solidification of liquids
Answer: a. Melting of metals
In an electric room heat convector, the method of heating used is:
a. Convection
b. Radiation
c. Conduction
d. Advection
Answer: a. Convection
Heat is transferred simultaneously by conduction, convection, and radiation. (True/False)
Answer: True
The process of heat transfer during the reentry of satellites and missiles, at very high speeds, into the earth's atmosphere is known as:
a) Conduction
b) Convection
c) Radiation
d) None of the above
Answer: c) Radiation
Which of the following has the highest value of thermal conductivity?
a) Air
b) Water
c) Copper
d) Diamond
Answer: d) Diamond
The induction heating process is based on which of the following principles?
a) Joule's law
b) Newton's law
c) Faraday's law
d) Ohm's law
Answer: c) Faraday's law
Which of the following insulating materials is suitable for low-temperature applications?
a) Fiberglass
b) Asbestos
c) Calcium silicate
d) Mineral wool
Answer: d) Mineral wool
A non-dimensional number generally associated with natural convection heat transfer is:
a) Grashof number
b) Reynolds number
c) Nusselt number
d) Prandtl number
Answer: a) Grashof number
The temperature inside a furnace is usually measured by which of the following?
a) Thermocouple
b) Mercury thermometer
c) Alcohol thermometer
d) None of the above
Answer: a) Thermocouple
Which of the following will happen if the thickness of the refractory wall of the furnace is increased?
a) Heat transfer rate will increase
b) Heat transfer rate will decrease
c) No effect on heat transfer rate
d) Cannot be determined
Answer: b) Heat transfer rate will decrease
The material of the heating element for a furnace should have:
a) High melting point
b) Low specific heat
c) High thermal conductivity
d) High electrical resistivity
Answer: d) High electrical resistivity
In a resistance furnace, the atmosphere is:
a) Oxidizing
b) Reducing
c) Neutral
d) None of the above
Answer: d) None of the above
By which of the following methods can the temperature inside an arc furnace be varied?
a) Changing the voltage
b) Changing the current
c) Changing the electrode position
d) All of the above
Answer: d) All of the above
In induction heating, ______ is abnormally high.
a) Electric field intensity
b) Magnetic field intensity
c) Both a) and b)
d) None of the above
Answer: b) Magnetic field intensity
By the use of which of the following, high-frequency power supply for induction furnaces can be obtained?
a) Rectifier
b) Inverter
c) Transformer
d) Oscillator
Answer: d) Oscillator
Induction furnaces are employed for which of the following?
a) Melting of metals
b) Heat treatment of metals
c) Welding of metals
d) All of the above
Answer: a) Melting of metals
In an electric room heat convector, the method of heating used is:
a) Convection
b) Radiation
c) Conduction
d) None of the above
Answer: a) Convection
26. In a domestic cake baking oven the temperature is controlled by
27. In an electric press mica is used
28. Induction heating takes place in which of the following?
29. For heating element high resistivity material is chosen to
30. In resistance heating highest working temperature is obtained from heating elements made of
31. For intermittent work which of the following furnaces is suitable?
32. Due to which of the following reasons it is desirable to have a short arc length?
33. In the indirect resistance heating method, maximum heat transfer takes place by
34. Properly of low-temperature coefficient of the heating element is desired due to which of the following reasons?
35. Which of the following methods is used to control the temperature in resistance furnaces?
36. It is desirable to operate the arc furnaces at a power factor of
37. Radiations from a black body are proportional to
38. In an arc furnace the function of the choke is
39. Ajax Wyatt furnace is started when
40. In electric press, mica is used because it is _______ conductor of heat but/and ________ conductor of electricity.
41. Resistance variation method of temperature control is done by connecting resistance elements in
42. Hysteresis loss and eddy current loss are used in
43. In heating the ferromagnetic material by induction heating, heat is produced due to
44. Radiant heating is used for which of the following?
45. Which of the following devices is necessarily required for automatic temperature control in a furnace?
46. For radiant heating around 2250°C, the heating elements are made of
47. Which of the following is an advantage of eddy current heating?
48. The electrode of a direct arc furnace is made of
49. Direct arc furnaces have which of the following power factors?
50. Indirect arc furnace, which of the following has high value?