Calorific value of Hydrogen is 1,50,000 kj/kg . What does it mean ?

The magnitude of potential barrier of germanium is about 0.3eV.What does it mean?

What does 10^2 xx 10^5 means?

The total energy of an electron in the ground state of a hydrogen atom is -13.6 eV. : What do you mean by ground state of a hydro gen atom ?