A radio can tune in to any station in the \(7.5\) MHz to \(12\) MHz bands. What is the corresponding wavelength band?
1. \(40\) to \(25\) m
2. \(10\) to \(100\) m
3. \(50\) to \(60\) m
4. \(20\) to \(10\) m

Which physical quantity does not change in vacuum for X-rays?