Draw a nitrogen cycle and explain in short.
please help me

Air is contained in a variable-load piston-cylinder device equipped with a paddle wheel. initially, air is at 400 kpa and 17°c. the paddle wheel is now turned by an external electric motor until 75 kj/kg of work has been transferred to air. during this process, heat is transferred to maintain a constant air temperature while allowing the gas volume to triple. calculate the required amount of heat transfer in kj/kg.

Which of these metals are magnetic?

Estimate the magnitude of the electric field due to the proton in a hydrogen atom at a distance of 5.29×10 to the power of −11 m, the expected position of the electron in the atom.