421.  The flow in open channel is laminar if the Reynold number is
A. less than 500
B. more than 500
C.1000
D. none of these.

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422. For which of the following points the stability of a dam is checked?
A. Tension at the base
B. Overturning of the dam
C. Sliding of the dam
D. All of these.

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423. Pick up the correct statement from the following :
A. Stable equilibrium occures when the meta centre is higher than the centre of gravity of the floating body.
B. Unstable equilibrium occures when the meta centre is lower than the centre of gravity of the floating body.
C. Neutral equilibrium occurs when the meta centre coincides with the centre of gravity of the floating body
D. All of these.

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424.  For a conical body immersed length 1 in liquid, Piezometer having 2a apex angle and an the meta centric height is :
A. 3/4 / tan a
B. 3/4 / tan2
C. 4/31 tan3
D. 4/3 /2 tan a

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