5. Light from a distant star enters a telescope and then passes through a diffraction grating. Each component of the emerging dispersed light is focused onto a curved strip of film. The grating is located on the central axis of the setup. It is found that a red beam appears off axis, in the first-order (k = 1) spectrum, at an angle of 30. If the lines of the grating are separated by 0.8 x 10-6 m, the wavelength of the light is_