You will be given a passage, and your task is to generate a Yes/No question that is answerable based on the given passage.

[EX Q]: According to the theory of relativity, no information can travel faster than the speed of light in vacuum, but this does not mean that the refractive index cannot be lower than 1. The refractive index measures the phase velocity of light, which does not carry information. The phase velocity is the speed at which the crests of the wave move and can be faster than the speed of light in vacuum, and thereby give a refractive index below 1. This can occur close to resonance frequencies, for absorbing media, in plasmas, and for X-rays. In the X-ray regime the refractive indices are lower than but very close to 1 (exceptions close to some resonance frequencies). As an example, water has a refractive index of 6999999999740000000♠0.99999974 = 1 − 6993260000000000000♠2.6×10 for X-ray radiation at a photon energy of 6985480652946099999♠30 keV (0.04 nm wavelength).
[EX A]: can a refractive index be less than 1?

[EX Q]: All Surface Pro 4 models come with a 64-bit version of Windows 10 Pro and a Microsoft Office 30-day trial. Windows 10 comes pre-installed with Mail, Calendar, People, Xbox (app), Photos, Movies and TV, Groove, and Microsoft Edge. With Windows 10, a ``Tablet mode'' is available when the Type Cover is detached from the device. In this mode, all windows are opened full-screen and the interface becomes more touch-centric.
[EX A]: does the surface pro 4 come with office?

[EX Q]: Crater Lake (Klamath: giiwas) is a caldera lake in south-central Oregon in the western United States. It is the main feature of Crater Lake National Park and is famous for its deep blue color and water clarity. The lake partly fills a nearly 2,148-foot (655 m)-deep caldera that was formed around 7,700 (± 150) years ago by the collapse of the volcano Mount Mazama. There are no rivers flowing into or out of the lake; the evaporation is compensated for by rain and snowfall at a rate such that the total amount of water is replaced every 250 years. With a depth of 1,949 feet (594 m), the lake is the deepest in the United States. In the world, it ranks ninth for maximum depth, and third for mean (average) depth.
[EX A]:
is crater lake the deepest lake in the world?