The FIRST and the LAST sentences of the paragraph are numbered 1 & 6. The others, labelled as P, Q, R and S are given below:
1. The word “symmetry” is used here with a special meaning, and therefore needs to be defined.
P. For instance, if we look at a vase that is left-and-right symmetrical, then turn it 180⁰ around the vertical axis, it looks at the same.
Q. When we have a picture symmetrical, one side is somehow the same as the other side.
R. When is a thing symmetrical – how can we define it?
S. Professor Hermann Weyl has given this definition of symmetry: a thing is symmetrical if one can subject it to a certain operation and it appears exactly the same after operation.
6. We shall adopt the definition of symmetry in Weyl’s more general form, and in that form we shall discuss symmetry of physical laws.
Which of the following combinations is the MOST LOGICALLY ORDERED?
Answer: D
The first sentence of the passage introduces the word “symmetry” and throws some light on the need for an elaborate definition of the word. Hence, only sentence R could be the next probable sentence as it begins to define the word “symmetry”. This is followed by sentence Q which puts forth a colloquial definition of symmetry. S-P ought to form a pair as S gives the definition of symmetry by Professor Herman Weyl and P gives an example to justify this definition. Therefore, the correct sequence is 1RQSP6.
Hence, the correct answer is option 4.