TPC 431

Question 1

Refrigeration is the process of _____________the air in a defined space.

Answer 1

Lowering the temperature of

Question 2

The temperature of a material decreases if the material ____________ and nothing else happens that would have the opposite effect.

Answer 2

Contacts a cooler material

Question 3

The two kinds of air conditioning are:

Answer 3

Comfort and process

Question 4

One of the physical states of matter is:

Answer 4

Gas

Question 5

You can cause matter to change its physical state by:

Answer 5

Adding or removing heat

Question 6

Thermal energy that is directly related to the temperature of a material is called _________heat.

Answer 6

Sensible

Question 7

A temperature of 45° is about the same as ____°C.

Answer 7

-7

Question 8

Heat can be transferred from one place to another by the process of:

Answer 8

Conduction

Question 9

The latent heat of vaporization of a substance is the amount of heat the substance absorbs as it:

Answer 9

Evaporates

Question 10

A refrigeration system has been turned off for several days. It contains both liquid refrigerant and vapor. Suddenly a line containing the refrigerant breaks. What happens inside the system?

Answer 10

The liquid refrigerant boils

Question 11

From the compressor, refrigerant flows to the:

Answer 11

Condenser

Question 12

Compared to a dry-expansion evaporator, a flooded evaporator of the same size is:

Answer 12

More efficient

Question 13

The purpose of a cooling medium is to:

Answer 13

Remove heat from compressed refrigerant vapor

Question 14

An automatic expansion valve is a metering device that maintains a constant pressure in the:

Answer 14

Evaporator

Question 15

The properties of air that are important in psychrometrics include:

Answer 15

Enthalpy

Question 16

In a sling psychrometer, the wet-bulb temperature is usually lower than the dry-bulb. If the difference is very small, you know that the air is quite:

Answer 16

Humid

Question 17

Air that is saturated is air that is at the:

Answer 17

Dewpoint temperature

Question 18

Relative humidity changes if the ______ changes, but the specific humidity does not.

Answer 18

Dry-bulb temperature

Question 19

To calculate the enthalpy of a sample of air, you must include:

Answer 19

Latent heat of the water vapor

Question 20

In order to remove the moisture that enters a refrigeration system during repair, you must evacuate the system by using a ______ to make all the moisture vaporize.

Answer 20

Vacuum pump

Question 21

One useful method of detecting leaks in a refrigeration system involves using a(n) _______ leak detector.

Answer 21

Electronic

Question 22

Relative humidity can be measured directly with a(n):

Answer 22

Hygrometer

Question 23

Which of the following is a correct match between an electrical value and the instrument used to measure it?

Answer 23

Resistance; ohmmeter

Question 24

In the list below, identify the line that correctly matches one of the classes of work-area hazard to an example of that class of hazard.

Answer 24

Chemical; container of refrigerant