To find the number of irrational numbers between \( \sqrt{11} \) and \( \sqrt{17} \), we first need to determine the approximate values of these square roots:
- \( \sqrt{11} \approx 3.3166 \)
- \( \sqrt{17} \approx 4.1231 \)
The interval between \( \sqrt{11} \) and \( \sqrt{17} \) is approximately \( (3.3166, 4.1231) \).
Since there are infinitely many irrational numbers in any interval of real numbers (as the real numbers are dense), there are indeed an infinite number of irrational numbers between \( \sqrt{11} \) and \( \sqrt{17} \).
Thus, the correct response is:
an infinite number.