(i) The set of lines which are parallel to the x-axis is an infinite set because lines parallel to the x-axis are infinite
in number.
(ii) The set of letters in the English alphabet is a finite set because it has 26 elements.
(iii) The set of numbers which are multiple of 5 is an infinite set because multiples of 5 are infinite in number.
(iv) The set of animals living on the earth is a finite set because the number of animals living on the earth is finite
(although it is quite a big number).
(v) The set of circles passing through the origin (0, 0) is an infinite set because infinite number of circles can pass
through the origin.
Figures 9.20(a) and (b) refer to the steady flow of a (non-viscous) liquid. Which of the two figures is incorrect ? Why ?
Sets are of various types depending on their features. They are as follows: