The electric field and magnetic fields deflect only charged particles. the X-rays, being electromagnetic radiation of short wavelength, are charge less. Hence, they are not deflected by electric and magnetic fields.

We do not notice the quantization of energy in everyday activities becausequantization means that particles are made up of a finite amount of units of energy. Also, quantization of energy is only seen in the atoms and atoms can only take up certain discrete values of energy.

When fast moving electrons strike on high atomic weight substance, X-rays areproduced and when radiations of sufficient frequency incident on the metal surface, electrons are emitted I.e.photoelectric effect take place. It means fast moving electronsproduce X-ray and X-ray I.e.radiation produce photoelectrons. Hence X-ray is the reverse phenomena of photoelectric effect

If the wavelength of electromagnetic waves lies between 4000Å to 8000Å, then such types of waves are visible. But the wavelength of X-rays lies between 1Å to 300 Å, Hence they are invisible.

If the atom is in ground state(n=1), there is no state of lower energy to which a downward transition can occur. Thus an atom in ground state are stable.