3. Bloodroot. This plant, which is sometimes referred to as redroot, is ground in eastern woodlands. It is often found near mayapple or Solomonâs Seal. Bloodroot has rounded green leaves and flowers with tiny white petals. However, it is the root part of the plant that is used for medicinal purposes.
If you shout hello, the sound may bounce back at you from a large object. You then hear your own voice coming back. Your returning voice is called an echo. Radar and sonar are electronic devices that use the principle of an echo to detect and locate objects. Both radar and sonar locate objects from the echo of a signal that is bounced off the object. Radar uses radio waves, which are a type of electromagnetic energy. Sonar uses the echo principle by sending out sound waves underwater or through the human body to locate objects. Sound waves are a type of acoustic energy. Because of the different type of energy used in radar and sonar, each has its own applications.
What do we use infrared radiation, microwaves and radio waves for? Infrared radiation is used for carrying signals from remote handsets and inside optical fibres. We use microwaves to carry satellite TV programmes and mobile phone calls. Radio waves are used for radio and TV broadcasting, radio communications and mobile phone calls. What are the hazards of these types of electromagnetic radiation? Different types of electromagnetic radiation are hazardous in different ways.