Electric Heating MCQs

41. Which of the heating methods has a lagging power factor?

1. Resistance heating
2. Induction heating
3. Dielectric heating
4. Arc Heating

42. In a domestic cake baking oven, the temperature is controlled by

1. series-parallel operation
2. auto transformer
3. thermostat
4. voltage variation

43. A black body when heated to ____________ emits the maximum energy in the visible spectrum range.

1. 5000 °C
2. 3250 °C
3. 6250 °C
4. 8000 °C

44. Two electric processes are connected in parallel. The resistance of the first press is 100 Ω and that of the second is 300 Ω. The total current taken by both the presses is 4A. The ratio of currents taken by first : second will be equal to

1. 1 : 3
2. 2 : 3
3. 3 : 0.5
4. 3 : 1

45. In which of the following appliance does the heating effect of current appear as an undesirable side effect?

1. Immersion heater
2. Electric Iron
3. Vacuum cleaner
4. Electric oven

46. In which of the following appliances is the heating effect used?

1. Electric motor
2. Transformer
3. Electric furnace
4. Generator

47. Energy (in units) consumed by a heater of rating 1000W by operating if for a period of 2 hours will be

1. 1.5
2. 2
3. 2.5
4. 4

48. While selecting heating element, one should keep in the mind that its specific resistance should be

1. As low as possible
2. Zero
3. Moderate
4. High

49. For heating non conducting materials, __________ is preferred.

1. Eddy current heating
2. Arc heating
3. Dielectric heating
4. Induction heating

50. Electric heating is used in industry includes

1. Dielectric heating and power frequency and radiant heating
2. Dielectric heating
3. Radiant heating
4. Power frequency heating