Cardiac output: Class 11 practice
Cardiac output = stroke volume × heart rate. Read the method, follow the three worked examples, then try the six questions.
What you should know first
- Units
The idea behind cardiac output
Cardiac output = stroke volume × heart rate. A typical adult pumps about 70 mL per beat at 72 beats per minute, about 5 L per minute.
Step-by-step method
- Write stroke volume (mL/beat) and heart rate (beats/min).
- Multiply.
- Convert mL to L if needed.
Worked example 1 (Basic)
Stroke volume 66 mL and heart rate 88 beats/min. Find the cardiac output in L/min.
- 66 × 88 = 5808 mL/min
- = 5.81 L/min
- Answer: 5.81 L/min
Worked example 2 (Standard)
Cardiac output is 4.2 L/min at 85 beats/min. Find the stroke volume.
- 4200 ÷ 85
- Answer: 49.41 mL
Worked example 3 (Challenge)
How much blood does a heart with stroke volume 93 mL at 67 beats/min pump in 39 minutes?
- 6231 mL/min × 39
- Answer: 243.01 L
Common mistakes and misconceptions
- Adding instead of multiplying
- Forgetting mL → L
Practice questions
- (Basic) Stroke volume 88 mL and heart rate 76 beats/min. Find the cardiac output in L/min.
- (Basic) Stroke volume 90 mL and heart rate 73 beats/min. Find the cardiac output in L/min.
- (Standard) Cardiac output is 4.3 L/min at 77 beats/min. Find the stroke volume.
- (Standard) Cardiac output is 6.7 L/min at 84 beats/min. Find the stroke volume.
- (Challenge) How much blood does a heart with stroke volume 97 mL at 108 beats/min pump in 51 minutes?
- (Challenge) How much blood does a heart with stroke volume 83 mL at 95 beats/min pump in 26 minutes?
Answer key with full working
- Q1: 88 × 76 = 6688 mL/min → = 6.69 L/min → Answer: 6.69 L/min
- Q2: 90 × 73 = 6570 mL/min → = 6.57 L/min → Answer: 6.57 L/min
- Q3: 4300 ÷ 77 → Answer: 55.84 mL
- Q4: 6700 ÷ 84 → Answer: 79.76 mL
- Q5: 10476 mL/min × 51 → Answer: 534.28 L
- Q6: 7885 mL/min × 26 → Answer: 205.01 L
Syllabus note
This skill is listed under "Body Fluids and Circulation" for Class 11 in the NCERT/CBSE books. ICSE, IGCSE, IB and state boards may teach it in a different chapter or year.
Answers on this page are generated and automatically re-checked by a second, independent calculation. They have not been reviewed by a teacher — if you spot a problem, tell us on WhatsApp.
Related practice and notes
Frequently asked questions
Which chapter is cardiac output in?
"Body Fluids and Circulation", Class 11 Biology (NCERT/CBSE). Other boards may place it differently.
How were the answers checked?
Answers on this page are generated and automatically re-checked by a second, independent calculation. They have not been reviewed by a teacher — if you spot a problem, tell us on WhatsApp.