Yes, wired headphones emit more radio Frequency than wired headphones. This RF has a couple of effects on the human body.  When RF radiation is taken into the body at very big levels, heat is produced.  This may lead to damage and burns to bodily tissue. However, the RF emitted by the headphones may be very insignificant for it to cause any harm to you. You should avoid using headphones for a long time to avoid the effects of RF on your body.