What two things are needed to create an emission nebula? a) interstellar gas and dust b) hydrogen fusion and helium ionization c) cool stars and much interstellar dust d) hot stars and interstellar gas, particularly hydrogen e) hydrogen gas and carbon dust

What would be the strength of earth's gravitational field at a point where an 80.0 kg astronaut would experience a 80% reduction in weight

The device shows the relative humidity at 22°c. what’s the water vapor density if the maximum water vapor in air at this temperature is 20 grams/cubic meter? a device showing that at 22 degrees celsius the relative humidity is 58%. a. 11.6% b. 11.6 g/m3 c. 12.76% d. 12.76 g/m3 reset next

What is the ultimate purpose of the nuclear reaction in a nuclear power plant? -the reaction is used to create a magnetic field. -the reaction is used to create temperatures high enough to generate steam. -the reaction is used to create a high pressure system used to spin the turbine of the generator. -the reaction is used to prevent chain reactions. in a safety seminar at a nuclear power plant, a technician describes the procedure used if temperatures in the reactor become too high. what procedures should the technician describe? select all that apply. -more coolant will be pumped into the reactor. -the control rods will be taken out of the reactor. -the fuels rods will be lowered into the reactor. -the control rods will be lowered into the reactor. during a lab experiment demonstrating the relationship between pressure and water, mr. demming puts a beaker of water into a vacuum chamber. once the chamber is sealed, mr. demming turns the vacuum on. as the pump starts to take air out of the chamber, the air pressure inside drops relative to the pressure outside the chamber. after a few minutes, there is next to no air pressure in the chamber. what do you expect to observe in the experiment? -the beaker of water will crack. -the boiling point of the water will decrease and begin to boil at room temperature. -the boiling point of the water will increase, and will only boil at temperatures higher than 212 degrees f. -the liquid water will expand and spill out of the beaker since the air pressure no longer compresses the water molecules.