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Which of the following is a characteristic feature of karst topography?

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Plants which produce characteristic pneumatophores and show vivipary belong to:

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A small hole of area cross-section

2 m m^{2}

is present near the bottom of a fully filled open tank of height

2 m .

Taking

g = 10 m s^{- 2}

, the rate of flow of water through the open hole would be nearly

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Two identical cylindrical vessels are kept on the ground and each contain the same liquid of density

d

. The area of the base of both vessels is

S

but the height of liquid in one vessel is

x_{1}

and in the other

x_{2}

. When both cylinders are connected through a pipe of negligible volume very close to the bottom, the liquid flows from one vessel to the other until it comes to equilibrium at a new height. The change in energy of the system in the process is :

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Sweet potato is a modified

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Root hairs develop from the region of

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If the potential energy between two molecules is given by

U = \frac{A}{r^{6}} - \frac{B}{r^{12}},

then at equilibrium, separation between molecules, and the potential energy are:

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Two light balls are suspended as shown in figure. When a stream of air passes through the space between them, the distance between the balls will

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In old age arteries carrying blood in the human body become narrow resulting in an increase in the blood pressure. This follows from

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Assertion: In case of motion of an ideal fluid in a horizontal tube, where the area of cross-section is minimum, pressure is maximum.
Reason: Hydrostatic pressure in different ideal liquids at points of different depth can be same.

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A liquid flows through a horizontal tube as shown in figure. The velocities of the liquid in the two sections, which have areas of cross-section

A_{1}

and

A_{2}

, are

v_{1}

and

v_{2}

, respectively. The difference in the levels of the liquid in the two vertical tubes is

h

. Then

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A stream of water flowing horizontally with a speed of

15 m s^{- 1}

gushes out of a tube of cross-sectional area

10^{- 2} m^{2}

and hits a vertical wall normally. Assuming that it does not rebound from the wall, the force exerted on the wall by the impact of water is:

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The $U$ - tube shown has a uniform cross-section. A liquid is filled in the two arms up to heights $h_{1}$ and $h_{2}$ , and then the liquid is allowed to move. Neglect viscosity and surface tension. When the levels equalize in the two arms, the liquid will

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If the velocity head of a stream of water is equal to

10 cm

, then its speed of flow is (

g = 10 m s^{- 2}

)

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In steady horizontal flow

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Water is flowing continuously from a tap having an internal diameter

8 \times 10^{- 3} m .

The water velocity as it leaves the tap is 0.4 m/s. The diameter of the water stream at a distance

2 \times 10^{- 1}

m below the tap is close to

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In the figure (in the vertical plane) shown an ideal liquid is flowing through the tube which is of uniform area of cross-section. The liquid has velocities

v_{A}

and

v_{B}

and pressure

P_{A}

and

P_{B}

at points

A

and

B

respectively. Then,
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Water stands at level $A$ in the arrangement shown in the figure. What will happen if a jet of air is gently blown into the horizontal tube in the direction shown in the figure?

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Explain why
To keep a piece of paper horizontal, you should blow over, not under, it

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An aeroplane of mass

3 \times 10^{4}

kg and total wing area of

120 m^{2}

is in a level flight at some height. The difference in pressure between the upper and lower surface of its wings in kilo pascals is

(g = 10 m s^{- 2})

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A	B
$(A)$ Rocket propulsion	$(e)$ Bernoulli’s principal in fluid dynamics
$(B)$ Aeroplane	$(f)$ Total internal reflection of light
$(C)$ Optical fibers	$(g)$ Newton’s laws of motion
$(D)$ Fusion test reactor	$(h)$ Magnetic confinement of plasma
	$(i)$ Photoelectric effects

Which of the following is a characteristic feature of karst topography?

Important Questions on Work, Energy and Power

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