Photons of red light have a wavelength of approximately meters. The energy of a photon is inversely proportional to its wavelengt

Photons of red light have a wavelength of approximately  $$$7\times 10^{-7}$$ $ meters. The energy of a photon is inversely proportional to its wavelength. A photon with 2000 times the energy as a photon of red light will have a wavelength that can be written as  $$$a\cdot 10^b$$ $ meters, where  $$$1\le a < 10$$ $. (In other words, in scientific notation.) What is a + b written as a decimal?