APC APC Certifications DU0-001 Questions & Answers

• Question 141:

  Which statement is true about humidity?

  A. If the relative humidity is zero, there is no water vapor present.

  B. As the air temperature decreases, its ability to hold water increases.

  C. If the relative humidity is 50%, the air is holding all the water vapor it can.

  D. The amount of water that can be contained in the room air is fixed regardless of the room temperature.

  Correct Answer: A

• Question 142:

  What are the four operating modes of CRAC units?

  A. Cooling, heating, saturation, humidification

  B. Cooling, heating, dehumidification, saturation

  C. Cooling, heating, humidification, dehumidification

  D. Cooling, humidification, dehumidification, saturation

  Correct Answer: C

• Question 143:

  Which statement describes the term "saturation point"?

  A. When air reaches 100% relative humidity

  B. When air temperature exceeds 80 F (27C)

  C. When water appears on the data center floor

  D. When the air's dew point is twice the temperature

  Correct Answer: A

• Question 144:

  What characterizes the effect of high humidity levels in the data center?

  A. High humidity causes long term corrosion damage to data center equipment.

  B. The extent of corrosion damage depends upon average ambient temperature.

  C. The extent of corrosion damage depends upon the dry airflow pattern in the data center.

  D. High humidity causes immediate corrosion damage to equipment within the data center.

  Correct Answer: A

• Question 145:

  What does the term "short cycling" mean?

  A. The fire suppression system clean agents are running low and have not been recycled.

  B. Cool air from the CRAC bypasses the IT equipment and flows directly into the CRAC return air duct.

  C. The raised floor is obstructed with excess cables and cool air is not getting through the vented floor tiles.

  D. The UPS supplies less runtime than anticipated because of overall wear and tear on the internal batteries.

  Correct Answer: B

• Question 146:

  Which type of humidification system rapidly vibrates water to create a fog or mist that is introduced into the air?

  A. Infrared humidifier

  B. Ultrasonic humidifier

  C. Electromagnetic humidifier

  D. Steam canister humidifier

  Correct Answer: B

• Question 147:

  When constructing a new data center, what is a best practice for controlling the influence of outside humidity?

  A. Use water-based paints for the walls.

  B. Install vapor barriers in walls and around doors.

  C. Increase the number of doors leading out of the data center.

  D. Use 2 foot by 6 foot ( .61 meters by 1.83 meters) steel framing for the walls, floors, and ceilings.

  Correct Answer: B

• Question 148:

  When monitoring humidity levels in the data center, where is the single most important place to measure the humidity?

  A. Above the rack

  B. Below the rack

  C. The air intake on IT equipment

  D. The exhaust air coming out of the back of the IT equipment

  Correct Answer: C

• Question 149:

  How do non-insulated water pipes impact humidity in the data center?

  A. They can increase the humidity in the data center.

  B. They can decrease the humidity in the data center.

  C. They do not affect the overall humidity of the data center.

  D. The affect they have on humidity depends on whether the pipes are copper or steel.

  Correct Answer: A

• Question 150:

  Half of the room's CRACs are adding humidity, while the other half of the CRACs are working to reduce the humidity in the room.

  What is this phenomenon called?

  A. Rightsizing

  B. Redundancy

  C. Demand fighting

  D. Resource allocation

  Correct Answer: C