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PHXI10:MECHANICAL PROPERTIES OF FLUIDS

361156 This question has statement- 1 and statement-2. Of the four choices given after the statements, choose the one that best describes the two statements.
Statement-1: A capillary is dipped in a liquid and liquid rises to a height $h$ in it. As temperature of the liquid is raised, the height $h$ increases (if the density of the liquid and the angle of contact remain the same).
Statement-2: Surface tension of a liquid decreases with the rise in its temperature.

1 Statement-1 is ture, Statement-2 is true; Statement-2 is not the correct explanation for Statement-1.

2 Statement-1, is false, Statement-2 is true

3 Statement-1 is true, Statement-2 is false.

4 Statement-1 is ture, Statement-2 is true; Statement- 2 is the correct explanation for Statement-1.

Explanation:

Surface tension of a liquid decreases with the rise in temperature. At the boiling point of liquid, surface tension is zero.
Capillary rise $h = \frac{2 T \cos θ}{r d g}$
As surface tension $T$ decreases with rise in temperature hence capillary rise also decreases.

JEE - 2013

PHXI10:MECHANICAL PROPERTIES OF FLUIDS

361157 Water rises to a height $h$ is a capillary at the surface of earth. On the surface of the moon the height of water column in the same capillary is
$(g_{m} = \frac{g_{e}}{6})$

1 Zero

2

6 h

3

\frac{1}{6} h

4

h

Explanation:

$h = \frac{2 T \cos θ}{r d g}$
$∴ h α \frac{1}{g}$
$As \begin{aligned} g_{m} = \frac{g_{e}}{6} \\ ∴ h_{m} & = 6 h_{e} . \end{aligned}$

PHXI10:MECHANICAL PROPERTIES OF FLUIDS

361158 Wax is coated on the inner wall of a capillary tube and the tube is then dipped in water. Then, compared to the unwaxed capillary, the angle of contact $θ$ and the height $h$ upto which water rises change. These changes are:

1

θ

increases and

h

also increases

2

θ

decreases and

h

also decreases

3

θ

increaes and

h

decreases

4

θ

decreases and

h

increases

Explanation:

The capillary rise
$h = \frac{2 T \cos θ}{ρ r g}$
When water is on a waxy or oily surface $\cos θ$ is negative i.e., $90^{\circ} < θ < 180^{\circ}$ i.e., angle of contact $θ$ increases And for $θ > 90^{\circ}$ liquid level in capillary tube fall i.e., $h$ decreases.

JEE - 2013

PHXI10:MECHANICAL PROPERTIES OF FLUIDS

361159 The rise of liquid into capillary tube is $h_{1}$ . If the apparatus is taken in a lift moving up with acceleration, the height is $h_{2}$ , then

1

h_{1} = h_{2}

2

h_{1} > h_{2}

3

h_{2} > h_{1}

4

h_{2} = 0

PHXI10:MECHANICAL PROPERTIES OF FLUIDS

361156 This question has statement- 1 and statement-2. Of the four choices given after the statements, choose the one that best describes the two statements.
Statement-1: A capillary is dipped in a liquid and liquid rises to a height $h$ in it. As temperature of the liquid is raised, the height $h$ increases (if the density of the liquid and the angle of contact remain the same).
Statement-2: Surface tension of a liquid decreases with the rise in its temperature.

1 Statement-1 is ture, Statement-2 is true; Statement-2 is not the correct explanation for Statement-1.

2 Statement-1, is false, Statement-2 is true

3 Statement-1 is true, Statement-2 is false.

4 Statement-1 is ture, Statement-2 is true; Statement- 2 is the correct explanation for Statement-1.

Explanation:

Surface tension of a liquid decreases with the rise in temperature. At the boiling point of liquid, surface tension is zero.
Capillary rise $h = \frac{2 T \cos θ}{r d g}$
As surface tension $T$ decreases with rise in temperature hence capillary rise also decreases.

JEE - 2013

PHXI10:MECHANICAL PROPERTIES OF FLUIDS

361157 Water rises to a height $h$ is a capillary at the surface of earth. On the surface of the moon the height of water column in the same capillary is
$(g_{m} = \frac{g_{e}}{6})$

1 Zero

2

6 h

3

\frac{1}{6} h

4

h

Explanation:

$h = \frac{2 T \cos θ}{r d g}$
$∴ h α \frac{1}{g}$
$As \begin{aligned} g_{m} = \frac{g_{e}}{6} \\ ∴ h_{m} & = 6 h_{e} . \end{aligned}$

PHXI10:MECHANICAL PROPERTIES OF FLUIDS

361158 Wax is coated on the inner wall of a capillary tube and the tube is then dipped in water. Then, compared to the unwaxed capillary, the angle of contact $θ$ and the height $h$ upto which water rises change. These changes are:

1

θ

increases and

h

also increases

2

θ

decreases and

h

also decreases

3

θ

increaes and

h

decreases

4

θ

decreases and

h

increases

Explanation:

The capillary rise
$h = \frac{2 T \cos θ}{ρ r g}$
When water is on a waxy or oily surface $\cos θ$ is negative i.e., $90^{\circ} < θ < 180^{\circ}$ i.e., angle of contact $θ$ increases And for $θ > 90^{\circ}$ liquid level in capillary tube fall i.e., $h$ decreases.

JEE - 2013

PHXI10:MECHANICAL PROPERTIES OF FLUIDS

361159 The rise of liquid into capillary tube is $h_{1}$ . If the apparatus is taken in a lift moving up with acceleration, the height is $h_{2}$ , then

1

h_{1} = h_{2}

2

h_{1} > h_{2}

3

h_{2} > h_{1}

4

h_{2} = 0

PHXI10:MECHANICAL PROPERTIES OF FLUIDS

361156 This question has statement- 1 and statement-2. Of the four choices given after the statements, choose the one that best describes the two statements.
Statement-1: A capillary is dipped in a liquid and liquid rises to a height $h$ in it. As temperature of the liquid is raised, the height $h$ increases (if the density of the liquid and the angle of contact remain the same).
Statement-2: Surface tension of a liquid decreases with the rise in its temperature.

1 Statement-1 is ture, Statement-2 is true; Statement-2 is not the correct explanation for Statement-1.

2 Statement-1, is false, Statement-2 is true

3 Statement-1 is true, Statement-2 is false.

4 Statement-1 is ture, Statement-2 is true; Statement- 2 is the correct explanation for Statement-1.

Explanation:

Surface tension of a liquid decreases with the rise in temperature. At the boiling point of liquid, surface tension is zero.
Capillary rise $h = \frac{2 T \cos θ}{r d g}$
As surface tension $T$ decreases with rise in temperature hence capillary rise also decreases.

JEE - 2013

PHXI10:MECHANICAL PROPERTIES OF FLUIDS

361157 Water rises to a height $h$ is a capillary at the surface of earth. On the surface of the moon the height of water column in the same capillary is
$(g_{m} = \frac{g_{e}}{6})$

1 Zero

2

6 h

3

\frac{1}{6} h

4

h

Explanation:

$h = \frac{2 T \cos θ}{r d g}$
$∴ h α \frac{1}{g}$
$As \begin{aligned} g_{m} = \frac{g_{e}}{6} \\ ∴ h_{m} & = 6 h_{e} . \end{aligned}$

PHXI10:MECHANICAL PROPERTIES OF FLUIDS

361158 Wax is coated on the inner wall of a capillary tube and the tube is then dipped in water. Then, compared to the unwaxed capillary, the angle of contact $θ$ and the height $h$ upto which water rises change. These changes are:

1

θ

increases and

h

also increases

2

θ

decreases and

h

also decreases

3

θ

increaes and

h

decreases

4

θ

decreases and

h

increases

Explanation:

The capillary rise
$h = \frac{2 T \cos θ}{ρ r g}$
When water is on a waxy or oily surface $\cos θ$ is negative i.e., $90^{\circ} < θ < 180^{\circ}$ i.e., angle of contact $θ$ increases And for $θ > 90^{\circ}$ liquid level in capillary tube fall i.e., $h$ decreases.

JEE - 2013

PHXI10:MECHANICAL PROPERTIES OF FLUIDS

361159 The rise of liquid into capillary tube is $h_{1}$ . If the apparatus is taken in a lift moving up with acceleration, the height is $h_{2}$ , then

1

h_{1} = h_{2}

2

h_{1} > h_{2}

3

h_{2} > h_{1}

4

h_{2} = 0

PHXI10:MECHANICAL PROPERTIES OF FLUIDS

361156 This question has statement- 1 and statement-2. Of the four choices given after the statements, choose the one that best describes the two statements.
Statement-1: A capillary is dipped in a liquid and liquid rises to a height $h$ in it. As temperature of the liquid is raised, the height $h$ increases (if the density of the liquid and the angle of contact remain the same).
Statement-2: Surface tension of a liquid decreases with the rise in its temperature.

1 Statement-1 is ture, Statement-2 is true; Statement-2 is not the correct explanation for Statement-1.

2 Statement-1, is false, Statement-2 is true

3 Statement-1 is true, Statement-2 is false.

4 Statement-1 is ture, Statement-2 is true; Statement- 2 is the correct explanation for Statement-1.

Explanation:

Surface tension of a liquid decreases with the rise in temperature. At the boiling point of liquid, surface tension is zero.
Capillary rise $h = \frac{2 T \cos θ}{r d g}$
As surface tension $T$ decreases with rise in temperature hence capillary rise also decreases.

JEE - 2013

PHXI10:MECHANICAL PROPERTIES OF FLUIDS

361157 Water rises to a height $h$ is a capillary at the surface of earth. On the surface of the moon the height of water column in the same capillary is
$(g_{m} = \frac{g_{e}}{6})$

1 Zero

2

6 h

3

\frac{1}{6} h

4

h

Explanation:

$h = \frac{2 T \cos θ}{r d g}$
$∴ h α \frac{1}{g}$
$As \begin{aligned} g_{m} = \frac{g_{e}}{6} \\ ∴ h_{m} & = 6 h_{e} . \end{aligned}$

PHXI10:MECHANICAL PROPERTIES OF FLUIDS

361158 Wax is coated on the inner wall of a capillary tube and the tube is then dipped in water. Then, compared to the unwaxed capillary, the angle of contact $θ$ and the height $h$ upto which water rises change. These changes are:

1

θ

increases and

h

also increases

2

θ

decreases and

h

also decreases

3

θ

increaes and

h

decreases

4

θ

decreases and

h

increases

Explanation:

The capillary rise
$h = \frac{2 T \cos θ}{ρ r g}$
When water is on a waxy or oily surface $\cos θ$ is negative i.e., $90^{\circ} < θ < 180^{\circ}$ i.e., angle of contact $θ$ increases And for $θ > 90^{\circ}$ liquid level in capillary tube fall i.e., $h$ decreases.

JEE - 2013

PHXI10:MECHANICAL PROPERTIES OF FLUIDS

361159 The rise of liquid into capillary tube is $h_{1}$ . If the apparatus is taken in a lift moving up with acceleration, the height is $h_{2}$ , then

1

h_{1} = h_{2}

2

h_{1} > h_{2}

3

h_{2} > h_{1}

4

h_{2} = 0