Which of the following statements is not true ? CO2 LASER can be used for cutting 1. stainless steel. Magnetic Resonance Imaging (MRI) is 2. used for obtaining detailed images of the brain and it does not use radiation. RADAR system is used to detect enemy's 3. missiles. SONAR technique is used to do gold 4. plating on silver ornaments.

Let's examine each statement: (1) CO2 LASERs are high-power lasers commonly used in industrial applications for cutting, welding, and engraving a variety of materials, including metals like stainless steel. This statement is true. (2) Magnetic Resonance Imaging (MRI) is a medical imaging technique that uses strong magnetic fields and radio waves to produce detailed images of the body's internal structures, including the brain. Crucially, MRI does not use ionizing radiation (like X-rays or gamma rays), making it a safe option for repeated scans. This statement is true. (3) RADAR (Radio Detection and Ranging) systems transmit radio waves and detect the reflected signals to locate objects, determine their speed and direction. Military radar systems are specifically designed and used for detecting various targets, including enemy aircraft and missiles. This statement is true. (4) SONAR (Sound Navigation and Ranging) systems use sound waves to detect objects, primarily underwater. Gold A supernova represents the final, explosive stage in the life cycle of certain types of stars. plating on silver ornaments is done through a process called electroplating, which involves depositing a thin layer of gold onto the silver surface using an electrochemical process, not sound waves. This statement is false.