Final answer:
The statement is false; radio waves and visible light both travel at the same speed in a vacuum, which is the speed of light at approximately 3× 10^8 meters per second.
Step-by-step explanation:
The statement that radio waves travel in vacuum at a lower speed than visible light is false. All forms of electromagnetic radiation, including radio waves and visible light, travel at the same speed in a vacuum, which is approximately 3× 10^8 meters per second (the speed of light, denoted as 'c'). This speed is a fundamental constant of nature and is independent of the frequency or wavelength of the electromagnetic waves.
Radio waves fall on the low-frequency side of visible light on the electromagnetic spectrum, while violet light has a higher frequency and shorter wavelength than red light. Variations in speed of electromagnetic waves occur only when they pass through different mediums, not in a vacuum.