Well, an interesting question indeed.

The basic principle for the production of X-ray is by deccelerating very fast moving electrons, so here might arise a question what happens to the energy of electrons? The energy of electrons is transferred to X-rays(minimum) and Heat energy.

How do we deccelerate the fast moving electrons?

Simply by resistance force, for a fast moving electron, the energy possessed by it must be high, so we deccelerate the electrons by a target material which is of high...

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.

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.

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

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.

The flesh of meat made up from lighter elements but the bones are made from heavier elements. So, that X-rays penetrate through the flesh meat but not through the bones. Further, the penetrating power of X-rays can be controlled by controlling the voltage between cathode and the target. For a medical purposes, X-rays are produced in such a way that the X-rays penetrate through the flesh but not through bones.

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.