SoLVE ANY 5 OF ThE FOLLOWING
Answers
1. Ultrasonic devices are used to detect objects and measure distances. Ultrasound imaging or sonography is often used in medicine. In the nondestructive testing of products and structures, ultrasound is used to detect invisible flaws.
2. Exposure to large amounts of radioactivity can cause nausea, vomiting, hair loss, diarrhea, hemorrhage, destruction of the intestinal lining, central nervous system damage, and death. It also causes DNA damage and raises the risk of cancer, particularly in young children and fetuses.
3. The repetition of sound caused by its reflection of a hard surface is known as echo. Factors important to get a distinct echo are: The minimum distance between the source and reflector of sound should be 17m. The size of reflector must be large enough as compared to the wavelength of the sound wave.
4. SONAR is an acronym for the term ‘sound navigation ranging’. It is a technique that involves the usage of sound propagation for navigational purposes. It can also be used for the detection of distant objects and for communication with other objects. SONAR has a wide spectrum of underwater applications, including communication between submarines and navigation of submarines. The two types of technology that fall under the name ‘SONAR’ include passive SONAR (used to listen to the sounds made by underwater objects) and active SONAR (which involves the emission of sound waves and waiting for the echo to come back). The first person to use the concept of SONAR was Leonardo da Vinci who, in the year 1490, inserted a tube into the water in order to hear the sounds made by certain vessels.
5. Diamond : has a very high melting point (almost 4000°C). Very strong carbon-carbon covalent bonds have to be broken throughout the structure before melting occurs.
. diamond is very hard.
Charcoal : Charcoal is solid at room temperature.
Charcoal is solid at room temperature.It is black in colour.
Charcoal is solid at room temperature.It is black in colour.It has low density because of its porosity.
Charcoal is solid at room temperature.It is black in colour.It has low density because of its porosity.It is bad conductor of heat and electricity.
Fullerene : Fullerenes are molecules of carbon atoms with hollow shapes. ...
Fullerenes are molecules of carbon atoms with hollow shapes. ... There are weak intermolecular forces between molecules of buckminsterfullerene
Answer:
3.Ultrasonic devices are used to detect objects and measure distances. Ultrasound imaging or sonography is often used in medicine. In the nondestructive testing of products and structures, ultrasound is used to detect invisible flaws.
4.Harmful effects of radioactive substances are:
Radioactive substances affect the central nervous system.
Exposure to radioactive radiations for long periods can lead to hereditary defects.
They can penetrate the skin, and causes diseases like skin cancer, leukemia.
6.The repetition of sound caused by its reflection of a hard surface is known as echo. Factors important to get a distinct echo are:
The minimum distance between the source and reflector of sound should be 17m.
The size of reflector must be large enough as compared to the wavelength of the sound wave.
7.Sonar (sound navigation and ranging) is a technique that uses sound propagation (usually underwater, as in submarine navigation) to navigate, communicate with or detect objects on or under the surface of the water, such as other vessels.
Explanation:
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