The distance between individual light waves making contact with a room's surface depends on the wavelength of the light. The wavelength is the distance between consecutive peaks or troughs of a wave.
Different light sources emit light with different wavelengths. For example, visible light consists of a spectrum of wavelengths ranging from approximately 400 to 700 nanometers (nm). Red light has a longer wavelength, around 700 nm, while blue light has a shorter wavelength, around 400 nm.
In a room illuminated by a light source, such as an incandescent bulb or a fluorescent tube, the light waves are typically emitted in a continuous stream, creating a wavefront that reaches the surfaces of the room. The distance between individual light waves in this case would be approximately equal to the wavelength of the light.
So, for visible light, the distance between individual light waves making contact with the room's surface would be on the order of hundreds of nanometers. It's worth noting that the waves are propagating in a three-dimensional space, so they are not strictly "touching" the surface but rather interacting with it through absorption, reflection, or scattering.