How many seconds is the normal duration of a cardiac cycle?

Correct option is D

Ans. (d)
Sol. The normal duration of one cardiac cycle (which includes one complete heartbeat—atrial and ventricular systole and diastole) is about 0.8 seconds. This corresponds to an average heart rate of 72 beats per minute. Each cycle consists of atrial contraction (0.1 sec), ventricular contraction (0.3 sec), and joint relaxation (0.4 sec).
Explanation of each option:
· (a) 0.6 seconds – Slightly shorter than the normal duration.
· (b) 0.10 seconds – Only covers the atrial systole phase.
· (c) 0.4 seconds – Reflects the joint diastole phase (relaxation).
· (d) 0.8 seconds – Correct answer. Total duration of one full cardiac cycle.