Question

Direction: Each of the next items consists of two statements, one labeled as the 'Statements (I)' and the other as 'Statement (II)'. You are to examine these two statements carefully and select the answers to these items using the codes given below:

Statement (I): An economic channel section gives maximum discharge for a given cross-sectional area.
Statement (II): An economical channel section has a smooth surface with reduced friction.
Codes:

• A. Statement (I) is true but Statement (II) is false
• B. Both Statements (I) and Statement (II) are individually true and Statement (II) is the correct explanation of Statement (I)
• C. Statement (I) is false but Statement (II) is true
• D. Both Statement (I) and Statement (II) are individually true but Statement (II) is not the correct explanation of Statement (I)

Answer 1

The correct option is A Statement (I) is true but Statement (II) is false

(c) The surface doesn't need to be smooth in the economical section for reduced friction.
However, if the surface is smooth then it allows better discharge flow and increases efficiency.
The economic section must have a minimum wetted perimeter.