Laser When looking at Laser technology, 1. absorb energy from an 2. current or light to produce a beam of 3. , which is limited to a specific range of visible, infrared, or ultraviolet 4. . Its applications span across healthcare, industry, optical 5. , and everyday life.
Li-Fi Li-Fi is a bidirectional 6. system that transmit data via LED or 7. light, using a light source equipped with a 8. to transmit Internet signals. Its key advantages include 9. , speed, energy 10. , and 11. for human health.
Satellite Finally, satellite systems rely on signal propagation from a ground 12. up to a satellite and back down to Earth; during this process, the satellite amplifies signal and changes its 13. .
11.1 Say if the sentences are true (Vero) or false (Falso).
1. A laser is created when the nuclei of optical materials absorb energy from an electrical current or light.
2. The absorbed energy creates a very narrow beam of radiation.
3. Lasers have several applications.
4. Li-Fi can use both LED or infrared light to transmit data.
5. Li-Fi transmits Internet signals through radio waves.
6. Li-Fi technology offers a high level of security.
7. In satellite transmission the ground station acts like a repeater.
8. The ground station can only transmit signals.
11.2 Correct the false sentences from the previous exercise.aperta
Soluzione suggerita:1. False, It is created when the electrons of atoms absorb energy; 2. True; 3. True; 4. True; 5. False, It transmits Internet signals through light waves; 6. True; 7. False, The satellites act like repeaters; 8. False, It can receive and transmit signals.
12.1 Listen to the recording about barcode scanners and answer the question: how do barcode scanners work?aperta
Soluzione suggerita:They read the pattern of black and white on a price tag, and that pattern is matched to the individual product’s number in a database.
12.2 Listen to the recording about barcode scanners in the previous exercise and answer the question: what kind of information does the barcode number provide?aperta
Soluzione suggerita:It brings up the product name, price, and other details.
12.3 Listen to the recording about barcode scanners in Exercise 12.1 and answer the question: what benefit has laser brought to businesses?aperta
Soluzione suggerita:It has allowed businesses to save a great deal of time.
12.4 Listen to the recording about barcode scanners in Exercise 12.1 and answer the question: why does a barcode avoid recording an incorrect number?aperta
Soluzione suggerita:Because each barcode links to a unique number.