On ECG Paper Operating at Standard Speed, What is the Duration

Question

On ECG paper operating at standard speed, what is the duration of the large squares?
A) 0.2 seconds
B) 0.04 sec
C) 2 seconds
D) 0.4 sec

Accepted Answer

Each large square on ECG paper, when operating at the standard speed of 25 mm/sec, represents 0.2 seconds.