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GATE 2026 CE (CE1) – Question 23

Hydraulics · Channel hydraulics: specific energy, critical flow, uniform flow, hydraulic jump · 1 mark · Multiple select

Gradually Varied Flow (GVF) profiles in open channels given in Column 1 are to be matched with the water surface slopes in Column 2 in the table below.

Column 1 GVF ProfileColumn 2 Water Surface Slope
(P) M1(I) Positive
(Q) M2(II) Negative
(R) M3(III) Zero

Which of the following options is/are NOT correct?

  1. (P) – (I) ; (Q) – (II) ; (R) – (I)
  2. (P) – (I) ; (Q) – (II) ; (R) – (III)
  3. (P) – (II) ; (Q) – (I) ; (R) – (I)
  4. (P) – (I) ; (Q) – (III) ; (R) – (II)

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Correct answer: (B) (P) – (I) ; (Q) – (II) ; (R) – (III); (C) (P) – (II) ; (Q) – (I) ; (R) – (I); (D) (P) – (I) ; (Q) – (III) ; (R) – (II)

Explanation

On a mild slope the M1 and M3 profiles rise in the flow direction, so their water surface slope is positive, while M2 falls, so its slope is negative. So the correct matching is P with I, Q with II and R with I, which is option A. Options B, C and D each contain at least one wrong match, so they are the options that are not correct.