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.
1 - how many hours you must wait before taking another dose of acetaminophen. - 2  how many doses of acetaminophen you can take safely each day. - 3  when to stop taking acetaminophen and ask a doctor for help. 4  Never take more than directed, even if your pain or fever isnât any better.