Internet of Things MCQs – Set-1 | 50 questions on connected devices, sensors, messaging, gateways, connectivity, edge processing, and device security.
Mixed difficulty · Select one answer and open each explanation to review the concept.
What is the Internet of Things (IoT)?
A Connected physical devices exchange data
B A collection of printed manuals
C A group of offline calculators
D A type of computer screen
Answer: A. Connected physical devices exchange data. IoT describes physical devices with sensing, software, or connectivity that exchange data with other systems.
What does an IoT sensor do?
A Changes network routes
B Measures a physical condition
C Stores a cloud backup
D Creates a user account
Answer: B. Measures a physical condition. A sensor measures a physical quantity or condition such as temperature or motion.
What does an actuator do in an IoT system?
A Reads a database table
B Measures air pressure only
C Changes or controls something physically
D Encrypts network packets
Answer: C. Changes or controls something physically. An actuator turns a control signal into a physical action, such as opening a valve.
What is a microcontroller commonly used for in IoT devices?
A A large database server
B A remote cloud region
C A fiber-optic cable
D Control logic for small devices
Answer: D. Control logic for small devices. A microcontroller combines processing and control functions for embedded devices.
What is an embedded system usually built to do?
A Perform a dedicated device function
B Host every website
C Replace a public network
D Store unlimited cloud data
Answer: A. Perform a dedicated device function. An embedded system is designed to control or support a particular device or function.
Where does edge computing process data?
A Only in distant data centers
B Near devices or data sources
C Only inside a database
D On a printed circuit diagram
Answer: B. Near devices or data sources. Edge computing processes data close to where it is generated, which can reduce delay or network traffic.
What role can an IoT gateway perform?
A Act as a physical sensor
B Replace all cloud services
C Connect device networks to systems
D Generate battery charge
Answer: C. Connect device networks to systems. An IoT gateway can connect devices to wider networks or cloud services.
Why might an IoT gateway translate protocols?
A To enlarge a screen
B To increase sensor accuracy
C To change a device’s battery
D Connect devices across protocols
Answer: D. Connect devices across protocols. Protocol translation lets devices and systems using different communication methods exchange information.
What is telemetry in an IoT deployment?
A Device or system measurements
B A device’s product warranty
C A physical network cable
D A printed circuit label
Answer: A. Device or system measurements. Telemetry is measured operational data sent from devices or systems for monitoring and analysis.
Which messaging pattern does MQTT use?
A Point-to-point printing
B Publish and subscribe
C File-and-folder sharing
D Circuit switching
Answer: B. Publish and subscribe. MQTT is a client-server publish/subscribe messaging protocol used in IoT contexts.
What does an MQTT publisher do?
A Stores every broker password
B Measures a device’s temperature
C Sends messages to a broker
D Subscribes to every topic
Answer: C. Sends messages to a broker. A publisher sends messages that an MQTT broker can distribute to interested subscribers.
What does an MQTT subscriber receive?
A A processor update
B A device’s physical serial number
C Only its own published message
D Messages matching subscribed topics
Answer: D. Messages matching subscribed topics. Subscribers receive messages for topics to which they have subscribed.
What does an MQTT broker do?
A Routes messages between clients
B Measures sensor voltage
C Changes actuator hardware
D Creates device batteries
Answer: A. Routes messages between clients. An MQTT broker receives messages and routes them to clients subscribed to the matching topics.
What does MQTT QoS 0 provide?
A At least once delivery
B At most once delivery
C Exactly once delivery
D Guaranteed permanent storage
Answer: B. At most once delivery. QoS 0 delivers a message at most once, without a delivery acknowledgment.
What does MQTT QoS 1 provide?
A Exactly once delivery
B No message transmission
C At least once delivery
D Guaranteed ordering across topics
Answer: C. At least once delivery. QoS 1 uses acknowledgment so a message is delivered at least once, possibly more than once.
Which protocol was designed for constrained web devices and networks?
A FTP
B SMTP
C IMAP
D CoAP
Answer: D. CoAP. CoAP is a specialized web transfer protocol designed for constrained nodes and networks.
What does unique device identification help an IoT system do?
A Distinguish one device from another
B Increase its battery size
C Reduce physical sensor noise
D Change its radio frequency
Answer: A. Distinguish one device from another. Device identification lets systems recognize and manage individual IoT devices.
What happens during device provisioning?
A A sensor measures pressure
B Device enrollment and setup
C An actuator opens a valve
D A battery is physically replaced
Answer: B. Device enrollment and setup. Provisioning enrolls and configures a device so it can operate within a system.
What is an over-the-air (OTA) update?
A Physical sensor replacement
B A cloud billing report
C Software delivered over network
D A printed configuration guide
Answer: C. Software delivered over network. An OTA update delivers software or firmware to a device through a network connection.
Why use secure boot on an IoT device?
A To increase network range
B To store more sensor readings
C To keep every interface open
D To verify startup software integrity
Answer: D. To verify startup software integrity. Secure boot checks that startup software is trusted before allowing it to run.
What does device authentication establish?
A The identity of a device
B A sensor’s measurement unit
C The battery’s remaining lifetime
D The network’s total bandwidth
Answer: A. The identity of a device. Authentication verifies the identity of a device or other communicating party.
What does authorization decide after authentication?
A Which firmware is newest
B Permitted device actions
C Where a sensor is mounted
D How much data is measured
Answer: B. Permitted device actions. Authorization determines which resources or actions an authenticated identity may access.
Why encrypt IoT data in transit?
A Increase the sensor’s range
B Improve battery chemistry
C Protect information moving across networks
D Replace device authentication
Answer: C. Protect information moving across networks. Encryption in transit helps protect data from interception or unauthorized reading while it moves across networks.
What is one purpose of rotating device credentials?
A Increase sensor resolution
B Reduce radio interference
C Avoid collecting telemetry
D Limit exposed credential value
Answer: D. Limit exposed credential value. Credential rotation can reduce the period during which a compromised credential remains useful.
How can network segmentation help IoT security?
A Limit communication between device groups
B Make every device public
C Disable all software updates
D Increase sensor temperature
Answer: A. Limit communication between device groups. Segmentation restricts communication between network zones and can limit the impact of a compromised device.
Why plan for an IoT device’s full lifecycle?
A Devices never need maintenance
B Support deployment, updates, and retirement
C Identical code on all devices
D Sensors always remain accurate
Answer: B. Support deployment, updates, and retirement. Lifecycle planning covers device deployment, operation, updates, support, and eventual retirement.
What is a digital twin?
A A second physical sensor
B A wireless encryption key
C Digital representation of physical system
D A cloud storage bucket
Answer: C. Digital representation of physical system. A digital twin is a digital representation of a physical asset or process, often updated with operational data.
How can IoT data support predictive maintenance?
A By removing all equipment sensors
B By replacing every operator
C By disabling equipment logs
D By detecting patterns before failures
Answer: D. By detecting patterns before failures. Sensor trends can reveal conditions that indicate a likely equipment problem before it causes failure.
Which system is a common consumer IoT example?
A Smart home lighting
B A paper filing cabinet
C A manual door lock
D A printed road map
Answer: A. Smart home lighting. Connected lights, thermostats, and sensors are common smart-home IoT devices.
What does Industrial IoT (IIoT) connect?
A Only home entertainment devices
B Industrial equipment and systems
C Only public web pages
D Printed inventory cards
Answer: B. Industrial equipment and systems. IIoT applies connected sensing and control to industrial equipment and operations.
What does RFID use to identify or track tagged objects?
A A magnetic hard disk
B A visual screen pattern
C Radio-frequency communication
D A wired Ethernet cable
Answer: C. Radio-frequency communication. RFID uses radio-frequency communication between a reader and a tag.
How does NFC commonly differ from longer-range radio links?
A It uses a satellite orbit
B It requires a fiber cable
C Cloud systems only
D Very short-range communication
Answer: D. Very short-range communication. Near-field communication is designed for communication over a very short range.
What is Bluetooth Low Energy designed to support?
A Low-power short-range communication
B Long-distance satellite data only
C Wired industrial Ethernet
D Cloud database queries
Answer: A. Low-power short-range communication. Bluetooth Low Energy supports short-range wireless communication with low power use.
Which connection might a smart appliance use on a local network?
A NFC only
B Wi-Fi
C Coaxial television cable
D SATA
Answer: B. Wi-Fi. Wi-Fi can connect IoT devices to a local wireless network.
What does a low-power wide-area network (LPWAN) emphasize?
A High-resolution video streaming
B Short cable runs
C Long-range, low-power device communication
D Large desktop displays
Answer: C. Long-range, low-power device communication. LPWAN technologies are designed for long-range communication from low-power devices.
What does a mesh network allow participating devices to do?
A Use one central cable only
B Disable message forwarding
C Connect only to satellites
D Forward data through neighboring nodes
Answer: D. Forward data through neighboring nodes. Mesh nodes can forward data for one another, extending connectivity across an area.
What does cellular IoT use for connectivity?
A Mobile network infrastructure
B A USB-only cable
C A printed barcode
D An optical disc
Answer: A. Mobile network infrastructure. Cellular IoT uses cellular network infrastructure to connect devices.
Why is duty cycling useful for battery-powered sensors?
A It forces continuous radio use
B Components sleep between tasks
C It prevents all data collection
D It increases screen brightness
Answer: B. Components sleep between tasks. Duty cycling turns components on only when needed, helping conserve battery power.
What does sensor calibration help improve?
A A device’s cloud region
B A radio’s encryption key
C Measurement accuracy
D A user’s password length
Answer: C. Measurement accuracy. Calibration compares sensor readings with known references and helps improve measurement accuracy.
What can sensor noise cause?
A A longer device name
B A larger battery
C Faster software updates
D Variation in measured readings
Answer: D. Variation in measured readings. Sensor noise introduces unwanted variation into measured data.
Why combine edge and cloud processing?
A Local processing plus cloud analysis
B Prevent all device communication
C Keep data permanently offline
D Remove the need for sensors
Answer: A. Local processing plus cloud analysis. Edge processing can handle time-sensitive tasks locally while cloud services support storage and broader analysis.
What does interoperability allow IoT products to do?
A Use identical batteries
B Work together across different systems
C Avoid all configuration
D Operate without communication
Answer: B. Work together across different systems. Interoperability lets products or systems from different vendors exchange and use information.
Why does privacy matter in connected homes?
A It changes a router’s brand
B It guarantees device uptime
C Devices collect personal activity
D It eliminates software bugs
Answer: C. Devices collect personal activity. Connected devices may collect sensitive information about people and their activities.
What should a device’s cloud data pipeline do?
A Ignore missing or invalid readings
B Publish every raw value publicly
C Store only device names
D Validate and process incoming data
Answer: D. Validate and process incoming data. A data pipeline can validate, transform, and route device telemetry for later analysis.
Why are device logs useful?
A Troubleshoot behavior and security events
B Increase radio transmission power
C Replace firmware updates
D Measure only the screen size
Answer: A. Troubleshoot behavior and security events. Logs record device events that can help troubleshoot operation and investigate security issues.
How should IoT firmware updates be handled?
A Never update deployed devices
B Verify and securely install updates
C Accept every file without checks
D Share one default password
Answer: B. Verify and securely install updates. Secure update processes verify update authenticity and protect devices while installing new firmware.
Why should default IoT passwords be changed?
A To improve sensor calibration
B To increase network speed
C Often known or reused
D To activate a new battery
Answer: C. Often known or reused. Default credentials are often known to attackers or shared broadly, so they should be replaced.
What can an IoT safety mechanism do?
A Increase data collection automatically
B Ignore sensor failures
C Expose all device controls
D Move system to safe state
Answer: D. Move system to safe state. Safety mechanisms can move a device or process to a safe state when a fault is detected.
Which design choice supports long-lived IoT devices?
A Plan updates and ongoing support
B Ship with permanent default credentials
C Disable device identification
D Remove monitoring after launch
Answer: A. Plan updates and ongoing support. Long-lived devices need support plans for security updates, configuration, and monitoring.
Why maintain an inventory of deployed IoT devices?
A Track ownership and device status
B Increase wireless range
C Replace network gateways
D Change sensor calibration
Answer: A. Track ownership and device status. A device inventory helps operators track device identity, configuration, ownership, and support status.