Internet Of Things Iot Wireless Systems And Edgecloud Infrastructure

Bluetooth and Wi-Fi are both wireless technologies but they serve different purposes and have different characteristics. Bluetooth uses a 2.4 GHz radio frequency band, whereas Wi-Fi can use 2.4 GHz or 5 GHz frequency band, so statement (a) is correct. Statement (b) is incorrect because Bluetooth is primarily used for connecting devices and creating a personal area network (PAN), not for Wireless Local Area Networks (WLAN). Wi-Fi, on the other hand, is used for WLAN and for internet access, not for Wireless Wide Area Networks (WWAN). Statement (c) is also incorrect. Both Bluetooth and Wi-Fi technologies do not require the devices to be in the line of sight of each other.

**Statement 1 is correct.** Near Field Communication (NFC) is indeed a contactless communication technology that relies on electromagnetic radio fields to transmit data between devices in close proximity. **Statement 2 is incorrect.** NFC operates over a very short range, typically requiring devices to be within a few centimetres of each other for successful communication. A meter is far too large a distance for NFC to function effectively. **Statement 3 is correct.** NFC can employ encryption to safeguard sensitive information during transmission. This is an important security feature for applications like contactless payments. 

 **Statement 1 is correct:** Li-Fi (Light Fidelity) utilizes light waves for data transmission. It uses rapid flickering of light, invisible to the human eye, to carry information. **Statement 2 is correct:** Li-Fi is a wireless technology and has the potential to be significantly faster than Wi-Fi. While actual speeds depend on various factors, Li-Fi boasts theoretical speeds exceeding 100 Gbps compared to the current Wi-Fi standards offering up to 11 Gbps. Hence, option C is the correct answer.

Project Loon was an ambitious initiative by Loon LLC, a subsidiary of Alphabet Inc. (Google's parent company), aimed at providing internet connectivity to remote and underserved regions worldwide. The project deployed high-altitude balloons in the stratosphere, equipped with networking technology to create an aerial wireless network, functioning like floating cell towers. These balloons were designed to deliver internet access in disaster-hit areas and regions with poor infrastructure. However, despite its technological success, Project Loon was discontinued in January 2021 due to difficulties in achieving commercial sustainability. Hence, the correct answer is option B.

The scenario described involves various devices (smartphone, geyser, smart mirror, refrigerator, car, etc.) communicating with each other and with the user, and automatically performing tasks based on certain triggers. This is characteristic of the Internet of Things (IoT).  **Option B is correct:** Internet of Things (IoT) is a system of interrelated computing devices, mechanical and digital machines, objects, animals or people that are provided with unique identifiers (UIDs) and the ability to transfer data over a network without requiring human-to-human or human-to-computer interaction. **Option A is incorrect:** Border Gateway Protocol is a protocol used to exchange routing information across the internet and is not relevant to the scenario described. **Option C is incorrect:** Internet Protocol is a set of rules for sending and receiving messages at the Internet address level, but it doesn't cover the broad range of device intercommunication described in the scenario. **Option D is incorrect:** A Virtual Private Network is a technology for using the internet or another intermediate network to connect computers to isolated remote computer networks that would otherwise be inaccessible, which also doesn't fit the scenario.

* Cirrus clouds do not reflect a lot of solar radiation into space. As they form at high altitudes and cold temperatures, they trap long-wave radiation and have a climate impact similar to greenhouse gases. Thus, thinning cirrus clouds would reduce the absorption of infrared radiation and are proposed as a form of climate engineering to reduce global warming.  * Another proposed Geo-engineering technique involves injecting reflective sulphate aerosol particles into Earth's lower stratosphere to cast a small proportion of the inbound sunlight back into space and cool the planet off. Thus, both are climate engineering/ Geo-engineering techniques to reduce global warming.

**Statement 1 is correct.** Wearable devices can perform several tasks, and out of given options, all three are achievable. Many smartwatches and wearables with GPS functionality can track a person's location. This can be helpful for navigation, fitness tracking, or safety purposes. **Statement 2 is correct.** Wearable sleep trackers can monitor sleep patterns, including sleep duration, sleep stages (deep sleep, light sleep, REM sleep), and sleep quality. **Statement 3 is correct.** Some wearables can function as hearing aids, amplifying sounds and improving hearing for people with hearing loss. Therefore, the correct answer is 1, 2, and 3.

Out of the listed communication technologies, all three can be considered short-range devices/technologies. **Closed-Circuit Television (CCTV):** CCTV systems primarily use cables or wireless connections with a limited range, typically within a building or a designated area. **Radio Frequency Identification (RFID):** RFID uses radio waves to identify objects. The reading range of RFID tags depends on the specific technology but generally falls within the short-range category, from a few centimetres to a few meters. **Wireless Local Area Network (WLAN):** WLANs, commonly known as Wi-Fi networks, typically operate within a range of tens of meters indoors and up to hundreds of meters outdoors depending on factors like signal strength and frequency band. While the range might be slightly larger than the others on this list, WLANs still fall under the short-range classification compared to technologies like cellular networks or satellite communication.