Consider the following statements: 1. Light of longer wavelength is scattered much more than the light of shorter wavelength. 2. The speed of visible light in water is 0.95 times and speed in vacuum. 3. Radio waves are produced by rapidly oscillating electrical currents. 4. To detect the over speeding vehicles, police use the Doppler effect of reflected short radio waves Which of these statements are correct?

1. Statement 1 is incorrect. According to Rayleigh scattering, the amount of scattering is inversely proportional to the fourth power of the wavelength (${\lambda}^{-4}$). This means light of shorter wavelength (like blue and violet) is scattered much more than light of longer wavelength (like red and orange). This is why the sky appears blue. 2. Statement 2 is incorrect. The refractive index of water for visible light is approximately 1.33. The speed of light in a medium is the speed in vacuum divided by the refractive index (c/n). So, the speed of visible light in water is approximately c/1.33, which is about 0.75 times the speed in vacuum, not 0.95 times. 3. Statement 3 is correct. Radio waves are electromagnetic waves produced by the acceleration of electric charges, typically in rapidly oscillating electrical currents in antennas. 4. Statement 4 is correct. Police radar speed guns use the Doppler effect. They emit short radio waves (microwaves) which are reflected by the target vehicle. The change in frequency of the reflected wave due to the vehicle's motion (Doppler shift) is measured to determine its speed. 5. Therefore, statements 3 and 4 are correct.