Question: Absolute pressure  being equal to current atmospheric pressure means what?
Answer: "Below atmospheric"

Question: What is a torr equal to?
Answer: displacement of a millimeter of mercury

Question: What is another often used options to measure vacuum?
Answer: barometric scale

Question: Why is mercury the better option for liquid used in a Hydrostatic gauge?
Answer: its high density and low vapour pressure

Question: What is a vertical column of liquid in a tube which has different pressures at each end called?
Answer: Hydrostatic gauges

Question: What is a hydrostatic gauge used for?
Answer: measure pressures ranging from 1 torr (100 Pa) to above atmospheric

Question: Why is the McLeod gauge special?
Answer: can measure vacuums as high as 10−6 torr

Question: An indirect measurement of pressure is most often calibrated by what?
Answer: McLeod gauge

Question: The fact that gases ability to conduct heat decreases with pressure is used by what form of measurement?
Answer: Thermal conductivity gauges

Question: How is the wire filament in a Thermal conductivity gauge heated?
Answer: by running current through it

Question: What is a Pirani gauge sensitive to?
Answer: chemical composition of the gases being measured

Question: What is a RTD used for on a Thermal Conductivity gauge?
Answer: to measure the temperature of the filament

Question: A Pirani gauge is accurate within what ranges?
Answer: 10 torr to 10−3 torr

Question: What affects the number of ions in a gauge?
Answer: the pressure in the gauge

Question: What must be used for accurate measurement on the composition of gases at a high vacuums?
Answer: mass spectrometer must be used in conjunction with the ionization gauge

Question: What gauge is accurate from 10-2 torr to 10-9 torr?
Answer: Cold cathode gauges

Question: Why does a mass spectrometer need to be used with gauge to be accurate at high vacuum gas measurement?
Answer: composition of gases at high vacuums will usually be unpredictable

Question: What are the two types of Ion gauges?
Answer: hot cathode and cold cathode.

Question: density of oxygen like that of sea-level atmosphere is needed to do what?
Answer: sustain life at pressures much lower than atmospheric,

Question: What is the lowest altitude where acclimatization or a suit is not needed to prevent sickness in humans?
Answer: of up to 3 km

Question: When will a person or animal lose consciousness  when exposed to a vacuum?
Answer: after a few seconds

Question: A shuttle astronauts prevents ebullism at 2 kPa with what item?
Answer: the Crew Altitude Protection Suit (CAPS)

Question: What is the forming of gas bubbles in body fluids at a lowered pressure called?
Answer: ebullism

Question: What prevents body rupture at low altitude when human body is bloated by gas bubbles?
Answer: tissues are elastic and porous

Question: What can boil away in extreme vaccum exposure?
Answer: Some oils and greases

Question: How should the grain direct of metallic flanges run to flange faces?
Answer: parallel

Question: What are 2 metals that can be absorbed in an ultra high vacuum system?
Answer: stainless steel or titanium

Question: What becomes a concern in an ultra high vacuum system regarding aluminum or palladium?
Answer: water absorption

Question: The state with the lowest possible energy in quantum mechanics defines what ?
Answer: vacuum

Question: A vacuum state with no matter particles or photons is called what?
Answer: QED

Question: why is a QED vacuum impossible to achieve ?
Answer: impossible to eliminate all the blackbody photons

Question: What is a QCD?
Answer: vacuum of quantum chromodynamics,

Question: When are electric and magnetic fields with zero average values, but their variances are not at zero?
Answer: In QED vacuum

Question: What is a verified effect of vacuum fluctuation?
Answer: spontaneous emission

Question: what is  vacuum fluctuation?
Answer: virtual particles that hop into and out of existence

Question: Finite energy in a QED is called what?
Answer: vacuum energy

Question: What modifies can Coulomb's Law in a vacuum?
Answer: vacuum near an electric charge

Question: `Why does thermosphere past the Karman line vary so greatly?
Answer: due to space weather

Question: What is commonly known as the boundary of outer space?
Answer: the Kármán line

Question: What do Astrophysicists use to describe outer space beyond the karman line?
Answer: number density

Question: What is more significant than isotropic gas pressure past the Karman line?
Answer: radiation pressure from the Sun and the dynamic pressure of the solar winds

Question: What was the object to use first in widespread manner process of vacuum?
Answer: incandescent light bulb

Question: What is produced by a vacuum and used in electron beam welding and vacuum frying?
Answer: chemical inertness

Question: Hight to ultra-high vacuums removes what obstruction?
Answer: obstruction of air,

Question: How does freeze drying, distillation and metallurgy benefit from a deep vacuum?
Answer: Deep vacuum lowers the boiling point of liquids and promotes low temperature outgassing

Question: What are two things made possible by the electrical properties of vacuum?
Answer: electron microscopes and vacuum tubes

Question: What provides power assistance for auto brakes?
Answer: vacuum servo

Question: What are two available sources of vacuum on a moving airplane?
Answer: engine and an external venturi

Question: Why are the Attitude indicator and heading indicator vacuum-powered?
Answer: protection against loss of all (electrically powered) instruments,

Question: What does a manifold vacuum do on a car?
Answer: drive accessories

Question: What no longer used accessories were powered by vacuum?
Answer: vacuum-driven windscreen wipers and Autovac fuel pumps

Question: what is evaporation and sublimation in a vacuum?
Answer: outgassing

Question: Why can outgassing products ruin a space mission?
Answer: obscure optical instruments

Question: When does outgassing become important in all solid or liquid materials?
Answer: vacuum pressure falls below this vapour pressure

Question: Repeatedly closing off a compartment of a vacuum allows what?
Answer: continue evacuating a chamber indefinitely without requiring infinite growth

Question: How is a vacuum created inside of a manual water pump?
Answer: a mechanism expands a small sealed cavity

Question: Why is fluid in a manual pump pushed into the pumps cavity when a small sealed cavity is expanded?
Answer: Because of the pressure differential

Question: What are pumps based off principle of sealed compartment pulling,pushing and expanding called?
Answer: displacement pumps

Question: What pump can capture gases in a solid or absorbed state?
Answer: Entrapment pumps

Question: Entrapment pumps often work without seals, moving parts and what else?
Answer: no vibration.

Question: What pump has a higher quality vacuum than a positive displacement pump?
Answer: Momentum transfer pumps

Question: When multiple pumps are connected in series to produce higher vacuum it is called what?
Answer: stages

Question: The choice of seals, or chamber geometry ,for example impact a pump. Together these are options are called what?
Answer: vacuum technique

Question: What are two other relevant characteristics of a pumping system along with final pressure?
Answer: oil contamination, vibration

Question: What period followed the Han dynasty?
Answer: Three Kingdoms

Question: What dynasty came before the Han dynasty?
Answer: Qin

Question: Who founded the Han dynasty?
Answer: Liu Bang

Question: When did the Former Han period begin?
Answer: 206 BC

Question: When did the Later Han period end?
Answer: 220 AD

Question: When did the Qing dynasty fall?
Answer: AD 1911

Question: What innovation was acquired from the Qin?
Answer: commanderies

Question: What philosphy in education was sanctioned by the Chinese court?
Answer: Confucianism