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APEX EKG Test Exam Questions And Answers
|Latest Update 2026/27
Q1. What is the normal rate range for a sinus rhythm in a
healthy adult?
A. 40–60 bpm
B. 60–100 bpm
C. 100–120 bpm
D. 120–150 bpm
✅ Answer: B. 60–100 bpm
🧠 Rationale: The SA node typically discharges at a rate of 60–
100 times per minute, which generates a normal sinus rhythm.
Rates below are bradycardic; above are tachycardic.
Q2. Which lead is commonly used as the ground reference in a
standard 12-lead EKG?
,Page 2 of 62
A. LA
B. RA
C. RL
D. LL
✅ Answer: C. RL (Right Leg)
🧠 Rationale: The right leg electrode serves as the reference
point (ground) to reduce electrical interference (noise) in the EKG
signal.
Q3. A student correctly places the brown (or white)
electrode on the patient's chest. How many chest electrodes are
typically used in a 12-lead EKG?
A. 4
B. 6
C. 8
D. 10
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✅ Answer: B. 6
🧠 Rationale: A 12-lead EKG uses six precordial (chest)
electrodes (V1–V6). Combined with four limb leads (RA, LA, RL,
LL), they provide 12 different electrical views (leads) of the
heart.
Q4. Which of the following is not a standard bipolar limb lead?
A. Lead I
B. Lead II
C. Lead III
D. Lead aVL
✅ Answer: D. Lead aVL
🧠 Rationale: Bipolar limb leads (I, II, III) measure voltage
between two limb electrodes. Leads aVR, aVL, and aVF
are unipolar augmented leads that measure voltage from a
single enhanced electrode.
, Page 4 of 62
Q5. What is the normal duration of the PR interval on an EKG?
A. 0.04 – 0.10 seconds
B. 0.12 – 0.20 seconds
C. 0.20 – 0.30 seconds
D. 0.30 – 0.40 seconds
✅ Answer: B. 0.12 – 0.20 seconds
🧠 Rationale: The PR interval (normal 0.12–0.20s) reflects the
time for the impulse to travel from the SA node through the atria,
AV node, and His-Purkinje system to begin ventricular
depolarization.
Q6. On EKG paper, a small block (1 mm) at standard speed
(25 mm/sec) represents:
A. 0.04 seconds
B. 0.10 seconds
APEX EKG Test Exam Questions And Answers
|Latest Update 2026/27
Q1. What is the normal rate range for a sinus rhythm in a
healthy adult?
A. 40–60 bpm
B. 60–100 bpm
C. 100–120 bpm
D. 120–150 bpm
✅ Answer: B. 60–100 bpm
🧠 Rationale: The SA node typically discharges at a rate of 60–
100 times per minute, which generates a normal sinus rhythm.
Rates below are bradycardic; above are tachycardic.
Q2. Which lead is commonly used as the ground reference in a
standard 12-lead EKG?
,Page 2 of 62
A. LA
B. RA
C. RL
D. LL
✅ Answer: C. RL (Right Leg)
🧠 Rationale: The right leg electrode serves as the reference
point (ground) to reduce electrical interference (noise) in the EKG
signal.
Q3. A student correctly places the brown (or white)
electrode on the patient's chest. How many chest electrodes are
typically used in a 12-lead EKG?
A. 4
B. 6
C. 8
D. 10
,Page 3 of 62
✅ Answer: B. 6
🧠 Rationale: A 12-lead EKG uses six precordial (chest)
electrodes (V1–V6). Combined with four limb leads (RA, LA, RL,
LL), they provide 12 different electrical views (leads) of the
heart.
Q4. Which of the following is not a standard bipolar limb lead?
A. Lead I
B. Lead II
C. Lead III
D. Lead aVL
✅ Answer: D. Lead aVL
🧠 Rationale: Bipolar limb leads (I, II, III) measure voltage
between two limb electrodes. Leads aVR, aVL, and aVF
are unipolar augmented leads that measure voltage from a
single enhanced electrode.
, Page 4 of 62
Q5. What is the normal duration of the PR interval on an EKG?
A. 0.04 – 0.10 seconds
B. 0.12 – 0.20 seconds
C. 0.20 – 0.30 seconds
D. 0.30 – 0.40 seconds
✅ Answer: B. 0.12 – 0.20 seconds
🧠 Rationale: The PR interval (normal 0.12–0.20s) reflects the
time for the impulse to travel from the SA node through the atria,
AV node, and His-Purkinje system to begin ventricular
depolarization.
Q6. On EKG paper, a small block (1 mm) at standard speed
(25 mm/sec) represents:
A. 0.04 seconds
B. 0.10 seconds
