Question 1

Which of the following is an advantages of heating by electricity?

Accepted Answer

A)  quicker operation
B)  higher efficiency
C)  absence of flue gases
D)  all of the above B

Question 2

For the transmission of heat from one body to another

Accepted Answer

A)  temperature of the two bodies must be different
B)  both bodies must be solids
C)  both bodies must be in contact
D)  at least one of the bodies must have some source of heating A

Question 3

In the indirect resistance heating method, heat is delivered to the charge

Accepted Answer

A)  direcly
B)  by radiation
C)  by convection
D)  both (b)  and (c) . D

Question 4

...... method has leading power factor

Accepted Answer

A)  resistance heating
B)  dielectric heating
C)  arc heating
D)  induction heating

Question 5

Spot welding is used for

Accepted Answer

A)  thin metal sheets
B)  rough and irregular surfaces
C)  costings only
D)  thick sections

Question 6

The coreless induction furnace uses high-frequency electric supply in order to obtain high

Accepted Answer

A)  flux density
B)  eddy-current loss
C)  primary resistance
D)  power factor.

Question 7

Heat is transferred simultaneously by condition, convection and radiation

Accepted Answer

A)  inside boiler furnaces
B)  during melting of ice
C)  through the surface of the insulted pipe caring steam
D)  from refrigerator coils to freezer of a refrigerator

Question 8

The process of heat transfer during the re-entry of satellites and missiles, at very high speeds, into earth's atmosphere is known as

Accepted Answer

A)  ablation
B)  radiation
C)  viscous dissipation
D)  irradiation

Question 9

Electric ovens using heating elements of........................... can produce temperatures up to 3000°C

Accepted Answer

A)  nickel
B)  graphite
C)  chromium
D)  iron.

Question 10

Which of the following is the condition to use two compressors in the refrigeration system?

Accepted Answer

A)  the desired temperature is 3°c
B)  the desired temperature is -3°c
C)  the desired temperature is -50°c
D)  the desired temperature is -5°c

Question 11

Which of the following heating method is based on the transformer principle ?

Accepted Answer

A)  resistance heating
B)  eddy-current heating
C)  induction heating
D)  dielectric heating.

Question 12

Room air conditioners and packaged units are examples of

Accepted Answer

A)  direct expansion systems
B)  indirect expansion systems
C)  chilled water systems
D)  indirect contraction systems

Question 13

A perfect black body is one that

Accepted Answer

A)  transmits all incident radiations
B)  absorbs all incident radions
C)  reflects all incident radiations
D)  absorbs, reflects and transmits all incident radiations

Question 14

The process of extraction of the certain required amount of water from air is known as

Accepted Answer

A)  heating
B)  cooling
C)  humidification
D)  dehumidification

Question 15

Which of the following is capable of absorbing excess moisture from the air?

Accepted Answer

A)  silica gel
B)  charcoal
C)  salts of calcium or ammonia
D)  activated alumina

Question 16

Which of the following cooling towers possess maximum heat transfer from air to water?

Accepted Answer

A)  natural draft
B)  mechanical draft
C)  natural and mechanical draft
D)  atmospheric draft

Question 17

Which of the following furnace suffers from pinch effect?

Accepted Answer

A)  resistance furnace
B)  core type induction furnace
C)  coreless induction furnace
D)  vertical core type induction furnace.

Question 18

Centrifugal compressors are used to handle------------------ volume of refrigerant.

Accepted Answer

A)  small
B)  medium
C)  large
D)  very large

Question 19

Magnetic materials are heated with the help of

Accepted Answer

A)  hysteresis loss
B)  electric arc
C)  electric current
D)  radiation.

Question 20

Which of the following is true about the optimum effective temperature for human comfort?

Accepted Answer

A)  same in winter and summer
B)  not dependent on season
C)  lower in winter than in summer
D)  higher in winter than in summer

Exam 2: HVAC and Heating Systems: Understanding Compressors, Cooling Towers, Filters, and Heat Transfer Methods