Free RFID Practice Questions

Question 1

A tool-tracking pilot uses ordinary passive UHF labels that read reliably on cardboard. The same labels become unreadable when mounted directly on steel tools and read again after removal without visible damage. Reader settings and label orientation are unchanged. What is the best next step?

Accepted Answer

Test an on-metal UHF tag using the manufacturer's specified mounting.

Answer

Increase reader power with the existing labels still mounted flush on steel.

Answer

Fit a circularly polarized antenna and keep the existing labels flush on steel.

Answer

Suspend installation and return the label lot as defective.

Question 2

Carton labels remain facing a reader antenna, but their linear tag antennas can rotate freely within that plane. With a linearly polarized reader antenna, some orientations read well and others fall into deep nulls. The RF budget can accommodate the circular-to-linear polarization loss. Which antenna change best addresses this orientation dependence?

Accepted Answer

Use a circularly polarized antenna covering the same read zone.

Answer

Increase antenna gain without changing linear polarization.

Answer

Rotate the existing linear antenna by 90 degrees and keep that orientation fixed.

Answer

Use a narrower-beam linear antenna aimed at the center of the conveyor.

Question 3

An access system accepts a recording of a previously valid tag response, even though the original tag is absent. The reader-to-server connection already uses authenticated TLS. Replacement tags support cryptographic authentication. Which change directly prevents acceptance of the recorded response?

Accepted Answer

Require a keyed response bound to a new, unpredictable challenge for every authentication.

Answer

Encrypt the reader-to-server connection with a longer TLS key.

Answer

Check the received identifier against the authorized-tag list on every scan.

Answer

Require a valid CRC on each tag response before checking its identifier.

Question 4

The service complaint is specific: a reader resets as inventory begins, although its supply stays at 24.0 V. The reader requires 22.0-26.0 V at its input. Current rises from 0.25 A at idle to 2.0 A immediately before the reset. The outgoing and return conductors each have 0.60 ohm resistance. Ignoring other losses, which diagnosis follows from the input voltage during inventory?

Accepted Answer

21.6 V; cable drop takes the input below its operating range.

Answer

23.7 V; the idle-load voltage shows that cable drop is acceptable.

Answer

22.8 V; the input remains in range, so the reset needs a different explanation.

Answer

24.0 V; the regulated supply keeps the reader input within its operating range.

Question 5

Crates in cold storage must send unattended temperature-excursion alerts while they remain in storage. No interrogator will illuminate the tags there, and downloading a history when crates leave is insufficient. Which architecture meets the reporting requirement?

Accepted Answer

Active sensor tags sending alerts to compatible receivers in the storage area.

Answer

Battery-assisted passive loggers read by a UHF portal when the crates leave storage.

Answer

Passive UHF sensor labels read by a handheld during scheduled warehouse rounds.

Answer

NFC temperature loggers read by staff during routine inspections of the crates.

Question 6

One reusable tote produces dozens of observations during a receiving passage. It can legitimately return through the same portal later that day under a different shipment. Receiving at this portal requires one receipt per tote per shipment, not one receipt per antenna read. Which middleware rule preserves both requirements?

Accepted Answer

Group observations by EPC, portal, and shipment, and create only one receipt for each group.

Answer

Group observations by EPC for the full day; issue one receipt per identifier.

Answer

Group observations by EPC and antenna; issue one receipt from each antenna.

Answer

Group observations by EPC and portal for the full day; disregard shipment changes.

Question 7

A Gen2 encoder writes a tote's new, same-length identifier to User memory, and a read-back confirms that write. Ordinary EPC inventory still reports the old identifier. The tag has writable EPC memory and no relevant locks. Which change makes ordinary inventory report the new identifier?

Accepted Answer

Write the new identifier to EPC memory, bank 01 in binary.

Answer

Write the new identifier to TID memory, bank 10 in binary.

Answer

Write the new identifier to Reserved memory, bank 00 in binary.

Answer

Repeat the write to User memory, bank 11 in binary, at higher power.

Question 8

Before replacing a photoeye, a technician stops an RFID-controlled conveyor at its operator panel. The reader's RF output is disabled, but the conveyor drive remains energized and a pneumatic diverter retains pressure. The repair requires reaching into the danger zone. Which action is required before starting the repair?

Accepted Answer

Isolate and lock out the sources, control stored energy, and verify isolation.

Answer

Engage the emergency stop and assign an operator to prevent a restart.

Answer

Disconnect the RFID reader and keep a second worker at the conveyor controls.

Answer

Disable automatic operation in software and retain manual control during repair.

Question 9

An approved antenna configuration has a 36 dBm EIRP ceiling. The reader supplies 29 dBm at its RF connector, the cable and connectors lose 2 dB, and the antenna gain is 8 dBi. All other authorization conditions are satisfied. Which power entry and operating decision belong in the commissioning record?

Accepted Answer

35 dBm EIRP; the setting meets the approved radiated-power ceiling.

Answer

39 dBm EIRP; suspend RF operation until the power setting is reduced.

Answer

27 dBm EIRP; increase output to use the available allowance.

Answer

37 dBm EIRP; reduce output before operating with this antenna.

Question 10

Readability mapping around a UHF portal reveals narrow dead spots between locations that read well. Moving a tagged dry carton a few centimetres sideways restores reads without rotating it. Several known-good tags reproduce the pattern, and moving a nearby metal partition shifts the dead spots. Which explanation best fits the spatial evidence?

Accepted Answer

Destructive interference between direct and reflected RF paths.

Answer

Permanent damage to the tag ICs during label application.

Answer

A fixed polarization mismatch between the reader and tag antennas.

Answer

RF absorption by the contents of the tagged cartons.

Free RFID Practice Questions

Domain 1: Introduction to Radio Frequency Identification (RFID) Fundamentals

Question 1

Domain 2: RF Safety

Question 2

Domain 3: RF Fundamentals Applied in RFID

Question 3

Question 4

Domain 4: Communication Methods and Protocol in RFID

Question 5

Domain 5: Tag Characteristics

Question 6

Domain 6: Fundamentals of Interrogator Communications

Question 7

Domain 7: RFID System Design Selection and Installation

Question 8

Domain 8: RFID Standards and Regulations

Question 9

Domain 10: Troubleshooting an RFID System

Question 10

The rest of the RFID blueprint

That's 10 of 1,030