WAEC Physics 2011 Paper

Concept:All electromagnetic waves travel at the speed of light in a vacuum.Explanation:Radio waves have lower frequencies and longer wavelengths than X-rays.So Option A is incorrect because radio waves do not have longer frequencies than X-rays.Option B is incorrect because X-rays do not have the longest wavelength; radio waves do.In a vacuum, every electromagnetic wave travels at $3.0 \times 10^{8}\ \mathrm{m\,s}^{-1}$.Hence, Option C is the correct statement.White light is visible light, and it lies between infrared and ultraviolet rays, not beyond ultraviolet.So Option D is also incorrect.Answer:C. some of the waves travel at $3.0 \times 10^{8}\ \mathrm{m\,s}^{-1}$