How does humidity affect air pressure?
- Humid air is heavier than dry air
- Humid air is lighter than dry air
- Humidity does not affect air pressure
- Humidity makes air pressure higher
Right Answer: (B) Humid air is lighter than dry air
What are the continuous lines on weather charts showing air pressure called?
- Isotherms
- Gradients
- Isobars
- Millibars
Right Answer: (C) Isobars
What unit is used to express air pressure on modern weather charts?
- Millibars
- Centimeters
- Kilograms per cubic meter
- Inches of mercury
Right Answer: (A) Millibars
Why is water not used in barometers instead of mercury?
- Water is heavier than mercury
- Water evaporates and is unsuitable for accurate readings
- Water does not rise as high as mercury
- Water is too expensive to use
Right Answer: (B) Water evaporates and is unsuitable for accurate readings
How high can a typical air pressure support a column of water?
- 28 feet
- 30 feet
- 34 feet
- 50 feet
Right Answer: (C) 34 feet
What principle is used to apply the brakes in a vacuum brake on railway trains?
- Electrical pressure
- Water pressure
- Steam pressure
- Air pressure
Right Answer: (D) Air pressure
What is an ejector used for in vacuum systems?
- To pump air out of a container
- To add air into a system
- To increase air pressure
- To produce a vacuum by passing steam
Right Answer: (D) To produce a vacuum by passing steam
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