How much energy does the em radiation have?

The answer is that different frequencies of EM waves carry different amounts of energy. The energy of an EM wave depends on its frequency. High-frequency, short-wavelength EM waves have more energy than low-frequency, long-wavelength waves. A high-frequency EM waves carries a lot of energy, so it has the possibility of damaging living tissue. But low-frequency wave carries much less energy, and is safer.