Written by Saurav
Description: An article about s police siren on their cars
Instructions: Read the short article below and answer the questions or fill in the spaces.
A siren is a device that makes a loud noise. It is used to get people’s attention. Sirens are used today in emergency service vehicles like ambulances, police cars and fire trucks. Most of the sirens are also used during a natural disaster or civil defence incident to alert people to danger.
There are two types of sirens. That is a pneumatic siren and an electronic siren. These sirens are mounted on the top of a vehicle. A pneumatic siren consists of a rotating disk with holes in it. As the holes in the rotating disk alternately prevent and allow air to flow it results in alternating compressed and rarefied air pressure which makes the sound. Electronic sirens are made up off circuits. The main components are oscillators, modulators and amplifiers.
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1. There are two types of sirens.CorrectIncorrect
2. Sirens are used to alert people.CorrectIncorrect
3. A siren is a device that does not make a loud noise.CorrectIncorrect
4. Sirens are commonly mounted on the rear end of the vehicles.CorrectIncorrect
5. Sirens are not used during natural disaster or civil defence incidents to alert people of the danger.CorrectIncorrect
6. Sirens are used today in emergency service vehicles like ambulances, police cars and fire trucks.CorrectIncorrect
7. A pneumatic siren consists of a rotating disk with holes in it.CorrectIncorrect
8. The main components of electronic sirens are oscillators, amplifiers and modulators.CorrectIncorrect
9. Electronic sirens are made up off circuits.CorrectIncorrect
10. Holes in the pneumatic siren allow air pressure to flow through it, resulting sound.CorrectIncorrect