The electromagnetic (EM) spectrum is the range of all types of EM radiation. Radiation is energy that travels and spreads out as it goes  the visible light that comes from a lamp in your house and the radio waves that come from a radio station are two types of electromagnetic radiation.
According to my doctor, 4 hours. You can switch them up. Take acetaminophen, (Tylenol), then wait 4 hours and take Ibuprofen, wait another 4 hours and take acetaminophen and sâ¦o on.
There are other times when you might want to switch from one to the other, too. Let's say you gave your child ibuprofen an hour or two ago, and her fever is still high or she's no more comfortable than she was before she took the medicine. In this instance, it's okay to give acetaminophen a try now. In fact, because you can't give her ibuprofen again for six to eight hours after the first dose, it may be helpful to try a new tack. If the acetaminophen does the trick, your child won't need any medication at all for another six to eight hours.