A soil moisture sensor in a remote field must transmit a small reading once per hour and run on a coin-cell battery for 5 years. Which wireless protocol is most appropriate?

Wi-Fi (802.11n) Bluetooth Classic LoRa (Long Range) Zigbee

Bluetooth Low Energy (BLE) is preferred over Bluetooth Classic for wearable fitness trackers because:

BLE has longer range than Bluetooth Classic BLE uses very little power when idle, allowing weeks of operation on a small battery BLE transmits at higher data rates than Bluetooth Classic BLE operates at 5 GHz, avoiding interference with Wi-Fi

In a Zigbee smart home network, a light switch 20 m away from the hub cannot connect directly. What feature of Zigbee solves this?

Zigbee automatically boosts its transmit power to bridge the gap Zigbee switches to a lower frequency with better wall penetration Mesh networking — other Zigbee devices relay the signal to extend range The hub polls every device every second to retrieve data

In the MQTT protocol, a temperature sensor publishes readings to the topic 'building/floor3/room7/temperature'. A dashboard subscribes to 'building/floor3/#'. Which messages will the dashboard receive?

Only messages from exactly 'building/floor3/#' as a literal topic All messages from any topic starting with 'building/floor3/' Only messages from 'building/floor3/room7/temperature' All messages from all floors in the building

Which of the following is a significant security risk specific to IoT devices?

IoT devices transmit too much data for network infrastructure to handle Devices shipped with default usernames and passwords that users never change IoT devices cannot be connected to the internet without a VPN LoRa encryption is incompatible with cloud platforms

Edge computing in an IoT system means:

Using the fastest available cloud server to process data before sending to devices Processing data locally on the device or gateway, close to where it is generated, rather than sending raw data to the cloud Positioning cloud servers at the edge of cities for lower latency Limiting IoT devices to the edge of a building's Wi-Fi coverage

NB-IoT (Narrowband IoT) uses licensed cellular spectrum. What advantage does this give over unlicensed-band protocols like Zigbee or LoRa?

NB-IoT devices are completely free to deploy with no ongoing costs NB-IoT operates at higher data rates than Wi-Fi Guaranteed, interference-free spectrum with wide geographic coverage using existing cell towers NB-IoT devices can update their firmware without any connectivity

A smart electricity meter sends daily usage data using MQTT with QoS level 1. What does QoS 1 guarantee?

The message is delivered exactly once with a two-way handshake The message may be lost if the broker is unavailable The message is delivered at least once; the receiver sends an acknowledgement The message is encrypted end-to-end before delivery

The Matter protocol (formerly Project CHIP) was developed to address which major IoT challenge?

Security — providing mandatory end-to-end encryption for all IoT traffic Interoperability — allowing smart home devices from different manufacturers to work together Power efficiency — reducing battery consumption by 90% across all protocols Range — enabling LoRa-class ranges for Wi-Fi devices

A factory has 500 vibration sensors on rotating machinery. Each sensor generates 50 kB of data per second. If all sensors send raw data to the cloud, what is the total required bandwidth?

500 kB/s (4 Mbps) 2.5 MB/s (20 Mbps) 25 MB/s (200 Mbps) 250 MB/s (2 Gbps)

Why does a Nest thermostat qualify as an IoT device and represent a successful engineering case study?

It uses a touchscreen instead of physical dials, making it an IoT device It connects to the internet to enable remote control, learns usage patterns using algorithms, and saves energy by adjusting heating and cooling automatically It replaces the HVAC system entirely with a solid-state cooling unit It uses Zigbee to communicate directly with smart bulbs and appliances

What is the primary advantage of using TLS (Transport Layer Security) for MQTT communication between an IoT device and a cloud broker?

TLS compresses MQTT messages to reduce bandwidth usage TLS encrypts data in transit and authenticates the server, preventing eavesdropping and man-in-the-middle attacks TLS increases the MQTT message delivery speed by reducing packet overhead TLS is only needed for MQTT QoS level 2 messages