Wavelength of UVB rays is ?
Ans. is 'a' i.e., 290 - 320 nm UV rays are used directly to treat skin conditions. It is simply referred to as phototherapy. These may be :? UVB phototherapy (290-320 nm) Narrow band UVB phototherapy (311 nm) UVA1 phototherapy (360-380 nm)
290 - 320 nm
320 - 360 nm
360 - 390 nm
390 - 420 nm